AKA Angelfish Aids, Angel Virus

This can be a very virulent and devastating disease.
All exposed angelfish that are not immune will come down with symptoms within 2-4 days of exposure, often quicker as “Angelfish Aids” is highly infectious. I witnessed many angelfish from fish farms in Southeast Asia that came in as carriers of this virulent infection in the 1990s; as a result many large angelfish breeding operations closed and there was a shortage of angelfish in the retail trade. I found some small scale angelfish breeders that were able to avoid exposure to this virus and keep me and others supplied with healthy stock

SYMPTOMS:

Clamped fins, excess slime, listless with nose pointed up slightly, usually with the fish on the bottom of the aquarium (unlike Gill Flukes which would have the fish at the surface). It has an approximately 3 week infectious period. This disease is quite virulent and if an angelfish survives the virus, it may become a carrier for up to six months. These symptoms can also be caused by other infectious diseases such as Ichthyophonus fungi infections (which are internal), but show similar external symptoms in later stages of the disease. However one major difference in external symptoms is that the progression of Angelfish Aids/Virus is much quicker than Ichthyophonus, often going from healthy and vibrant to sickly to death in as little as 5 days.
Do not also confuse Angelfish Aids/Virus with internal worm infections such as Nematodes or Annelids as these parasitic worm infections often have a bulge in the lower abdomen near the vent, or worms protruding from the anus, as well the progression is again generally not nearly as quick as Angelfish Virus/Aids (often internal parasite infections can go on for weeks of slowly more noticeable symptoms). Parasites such as Gill Flukes cause some similar symptoms, although again the progression of Gill Fluke symptoms is much slower than Angelfish Virus (often gill fluke symptoms slowly appear over a week or more time)

If you suspect that a quarantined fish has this virus, I recommend that you destroy the fish. The risk of spread is too high to keep a potentially infected fish around.

Here is a video of the fish pictured above in a video format; this fish is showing most of the classic symptoms of Angelfish Virus from which I have seen many times (especially during outbreaks during the 1990s). I also sent the video link to friend in the professional maintenance business that confirmed this. The other possible diagnosis is Gill Flukes, however as per the owner of this angelfish, the progression of the disease, nor the fish resting on the tank bottom does not indicate this diagnosis.

Video Courtesy DaharkazAngel

MODE OF DISEASE TRANSFER

This is where there is not clear evidence (scientific that is), all I have is my observations as well as speaking with other aquarium maintenance professionals experience and brief non-scientific articles about Angelfish Virus.
I will provide a few observations/theories (please note that these are not proven at the time of writing this article):

*Direct transfer in the water column; this seems to be the main mode of transference, which of coarse quarantine or purchasing of fish from a known good source can help prevent. As well I have noted that UV Sterilization has helped check the spread of Angelfish Aids to non-immune/exposed fish (which further supports this theory as a UV cannot prevent the spread via feces or similar)

*Transfer via infected water, decorations, or even plants; this is similar to the above and similar preventative measures as above should be taken to prevent this mode of transfer

*Transfer via direct contact/feces; I personally do not support this mode of transfer as I have not observed it nor has the few tests to check the spread bear this out, however a few knowledgeable persons I know (or read) have postulated this.

*Incubation of the virus; as noted in the symptoms section of this article, it has been espoused that a fish can be a carrier for up to six months

TREATMENT:

Since immunity is the objective, it is important to keep the angelfish comfortable while giving the immune system time to fight this virus (if it can). Part of the problem is this virus moves so fast, the fish’ immune system cannot respond quick enough, so optimal conditions is a must (and this includes the little known among aquarists parameter of Redox Balance which may be quite important for immunity during times of viral infection)
Secondary bacterial and Fungal/Saprolegnia infections are also often issues during Angelfish Aids infections from my experience.

Steps:
*Removal of any bright lights from the aquarium (a darkened quarantine tank is strongly recommended).
*A medicated Bath utilizing Methylene Blue is recommended
*Treatment (again preferable in quarantine for Angelfish Virus), may include a “cocktail” of SeaChem ParaGuard, Nitrofurazone, and Kanamycin
*Treat as the medications suggest until symptoms are gone plus 3 days
*Partial water changes between each treatment along with strict monitoring of water parameters (ammonia, nitrites, even GH & KH) is a must
*The addition of a UV Sterilizer to the main display tank while the fish are in quarantined is strongly urged to aid in stopping the water borne spread of the virus and improve Redox Balance.

SUMMARY:

Although I have given a method of treatment, please do not let me give the reader too much false hope; as even with strictly following this treatment regimen quite strictly, chances of success are less than 50% from my experience (many aquarists choose to put the fish down rather than to treat and this is a valid option in my humble opinion as well).
However I have also had success with this treatment regimen (much more so than doing nothing), so if you are willing or able to strictly follow it, you may have success.

Either way, with success, failure, or putting the fish down; prevention of spread to other angelfish (or some other fish as well) should be considered.
Multiple water changes, optimum water parameters, UV Sterilization, and holding off from adding other angelfish for 3-6 months should all be considered.

Use of Activated Carbon in Freshwater, Marine Aquariums and Ponds

Updated 10/12/09

Carbon is primarily an adsorbent which is a very popular chemical filter media that is often misunderstood as to use in established aquariums and ponds as well.
A healthy established aquarium (fresh or salt) with regular water changes generally needs little carbon (although more carbon is generally needed in marine reef aquariums and less in low pH freshwater aquariums). Carbon will NOT remove or absorb ammonia, nitrites, or nitrates. Carbon is very useful in removing medications after treatment or even between doses.


Please read the entire article for a good understanding of what activated carbon can or cannot do for your aquarium/pond; including the table of what carbon can and cannot remove as well as the referenced resources
How Activated Carbon Works

Activated carbon has an extremely large surface area per unit weight, which makes AC an extremely efficient absorptive AND adsorptive material. The activation of carbon and its manufacture creates many pores within the particles, and it is the vast areas of the walls within these pores that accounts for most of the total surface area of the carbon. In water, activated carbon has a preference for large organic molecules and for substances which are non-polar in nature. The forces of attraction between the carbon and the absorbed molecules are greater the closer the molecules are in size to the pores. The best absorption takes place when the pores are just large enough to admit the molecules.
Activated carbon, when contacted with water containing organic material, will remove these compounds selectively by a combination of adsorption of the less polar molecules, absorption (filtration) of the larger particles, and partial deposition of colloidal material on the exterior surface of the activated carbon.


As well as absorption, activated carbon uses a process called Adsorption, in fact adsorption is the primary method of molecule removal by carbon, not absorption.
When a material adsorbs something, it means it attaches it by chemical attraction.
The extent of removal of soluble organics by absorption depends on the diffusion of the particle to the external surface of the carbon and diffusion within the porous adsorbent. For colloidal particles, internal diffusion is relatively unimportant because of particle size.
Organic substances that pass through the column consist of hydrophilic organic molecules (substances that are attracted to, and dissolve well within, water) and hydrophobic molecules (repulsed by water). If the molecule is “polar” (having both a hydrophobic and hydrophilic attributes) which many organic molecules are, the hydrophobic side will be attracted (attached) to the activated carbon.
Adsorption is partially the result of forces of attraction at the surface of a particle that cause soluble organic materials to adhere to the activated carbon. The limited water solubility of many organic substances will affect AC adsorption of these molecules.

Put more simply (I hope): Polar, hydrophobic and hydrophilic interactions are important interactions necessary to understand how activated carbon adsorb the certain molecules. A Methylene Blue dye molecule is hydrophobic and has a large affinity to the hydrophobic carbon rings of the activated carbon. The dye prefers to interact with the carbon rather than water. Where as non chelated metals (such as copper ions) are positively charged (hydrophilic), and the carbon is neutral and hydrophobic. Therefore, the positively charged metal ions prefer to interact with the water, which is hydrophilic. “Like dissolves Like”.
This applies to most metals from the periodic table, including calcium, magnesium, etc., and for this reason most essential minerals are not removed by activated carbon unless chelated or if they loose their positive charge due to oxidative processes of the Redox Potential (which is another reason to replenish these positive mineral ions, please see this article for further information: The Aquarium Redox Potential)
This positive/negative ionization is why DOC (organics) will also negatively affect the Aquarium/Pond Redox Balance


Common Uses
As already noted healthy aquariums often do not need much activated carbon, however this is a rather ambiguous generalization. An aquarium keeper need to consider DOC (dissolved organic compounds/carbon), pH, desired compounds that can or cannot be removed, bio load of the aquarium or pond, desired environment (an Amazon River aquarium will generally need less or no carbon while a heavily fed reef tank will need more).
I have noted performed a controlled study of how much carbon is best however I have made many observations over the years in freshwater and marine aquariums of different environments, as well as ponds. I would use tests of pH/KH (which will tend towards lower pH/KH without carbon use), nitrates (although carbon cannot remove nitrates, it can remove DOC that will eventually end up as nitrates), even TOC or Redox tests if available (Methylene Blue can be used a Redox indicator, please see this article for much more about Redox: The Aquarium/Pond Redox).
Simply gauging carbon use by tank water color, can be a simple method to base carbon use by (admittedly very unscientific though).
The use of carbon if only for a day or even hours after or between medication treatments is another important aspect of carbon use.

In Reef aquariums, the use of carbon (even though less effective in higher pH water) is important in my experience/opinion as part of a regimen that where carbon is but one piece of the aquarium maintenance puzzle that often includes Protein Skimmers (which also remove many similar DOC, but not as quickly after production), water changes, micron filtration, de-nitrification (with deep sand beds or products such as Matrix), and use of chemical absorbents such as Purigen.

Carbon can also be used in mixed products such as Ammo Carb, but zeolites are only for freshwater use. The use of zeolite/carbon mixes is especially useful in areas where municipal tap water contains chloramines (instead of the usual chlorine). I have also achieved good results with carbon/zeolite blends in ponds which are generally exposed to even more contaminants than aquarium.

A good starting point for carbon use (please note that this is a generalization) is one to three teaspoons per ten gallons of water. One teaspoon of activated carbon is equal to approximately 6 grams in weight measurement. This amount will vary greatly depending upon many other factors that the aquarium or pond keeper can determine. As well sometimes an aquarium keeper may choose to only use this amount of carbon as part of a clean up procedure (in particular freshwater aquariums) and then discontinue use after a day or two. If you have an Aquarium Cleaning Machine, I and others will only use carbon in this machine for freshwater aquariums and not during normal tank operation.

Lignite Activated Carbon

The best Premium Activated Carbon is produced from a soft, brownish-black coal (Lignite) in which the alteration of vegetable matter which has proceeded further than in peat but not as far as in bituminous coal. Lignite based carbon is the best choice for use in aquarium & ponds to remove organic molecules, pesticides and for color removal, due to its large pore size. The large pore size is important, because the organics in a aquarium or pond environment will clog and render ineffective, the smaller-pored, coconut shell and Testing has shown other Activated Carbons; such Large pelletized, to be almost useless for aquarium or pond water, but excellent for Chlorine and Heavy metal removal in clear water applications such as swimming pools or drinking water.
6 grams (.21 ounces) of Lignite Activated Carbon has the surface area of a football field, so a little goes a long ways in aquarium use in particular.

Here are a few aspects that impact the effectiveness of activated carbon

Chemical Properties;
The carbon surface may actually interact chemically with organic molecules. As well electrical forces between the activated carbon surface and some contaminants may result in adsorption or ion exchange. Adsorption, then, is also affected by the chemical nature of the adsorbing surface. The chemical properties of the adsorbing surface are determined to a large extent by the activation process. Activated Carbon formed from different activation processes will have chemical properties that make them more or less attractive to various contaminants.

Contaminant Properties:
Large dissolved organic compounds/carbon (DOC) are most effectively adsorbed by activated carbon. A general rule of thumb is that similar materials tend to associate. DOC molecules and activated carbon are similar materials; therefore there is a stronger tendency for most organic chemicals to associate with the activated carbon in the filter rather than staying dissolved in a dissimilar material like water. Generally, the least soluble organic molecules (such as large complex amino acids or fatty acids) are most strongly adsorbed. Often the smaller organic molecules (such as sugars) are held the tightest, because they fit into the smaller pores.
It is also noteworthy that although larger complex organic molecules (often nitrogen based) are more readily absorbed, these molecules are also not held as tightly and re-leased under certain conditions which is why carbon should not be relied on for the sole form of organic contaminant removal. Other methods such as Purigen, de-nitrifying filters, water changes, Protein Skimmers (marine aquariums), micron filters, UV Sterilizers, etc. should be employed as part of the mix.

Concentration of organic contaminants can affect the adsorption process. A given activated carbon may be more effective than another type of activated carbon material at low contaminant concentrations, but may be less effective than the other carbon material at high concentrations.

Water Temperature and pH;
Adsorption usually increases as pH and temperature decrease. Chemical reactions and forms of chemicals are closely related to pH and temperature. When pH and temperature are lowered many organic chemicals are in a more absorbable form (this is noteworthy for marine/saltwater use and why Protein Skimmers are also important as these devices will remove DOC as well, although not immediately as carbon can)

Exposure Time;
The process of adsorption is also influenced by the length of time that the carbon is in contact with the contaminant in the water. Increasing contact time allows greater amounts of contaminant to be removed from the water. Contact is improved by increasing the amount of activated carbon in the filter and reducing the flow rate of water through the filter.

There is controversy in what essential minerals carbon will absorb or what activated carbon will or will not absorb in general. I will state based on my own experience and scientific evidence that carbon has many uses in aquariums/ponds but is also over used or incorrectly recommended. Although I use little carbon in my established healthy aquariums and ponds, I disagree with those that state it should not or rarely be used (based on some false assumptions of what carbon removes or adds to water). On the flip side I also disagree with those that make carbon the answer for water quality issues such as nitrates for which carbon does not remove.
Activated Carbon is very useful for removing most medications after or between treatments (this is where I strongly recommend its use), although even here, carbon does not remove most copper formulations effectively.


Possible Concerns with Carbon Use

*Activated carbon can foster the growth of bacteria by concentrating other organics (such as DOC) on its surface.
Although I have not performed controlled tests to confirm this, I have made many observations over the years that increased use of carbon has coincided with increased incidence of bacterial infections such as Aeromonas, especially in lower pH Amazon River & SE Asia water aquarium environments since Redox is also generally less favorable and the removal of tannins from products such as Indian Almond Leaf Extracts allows these bacteria to thrive.
The fact that activated carbon removes oxygen, further increases the risk of an opportunistic Aeromonas Bacterial outbreak since these bacterium are anaerobic.

*Use in planted freshwater aquariums:
This is an area of some controversy of which some information is based on facts, some information is not, with some reasonable questions in between.

The main controversy I will address for now as to carbon use in planted freshwater aquariums is the removal of trace minerals. I read some experiments at “the Krib”, as well I have made observations and tests (as well as research) over the years myself.
The main testable point is that most metals such as Iron (which is important for plants) are NOT absorbed carbon with an important and noteworthy exception; and that is the use of chelation. EDTA (which is an organic molecule) is used to chelate many metals such as iron to make it more readily available for fertilizers or other uses, and since activated carbon is especially effective in removing organic carbon based molecules, these chelated metals are then removed. Any aquatic plant fertilizers that contain chelated metals will be bound to the carbon pores, and as result their concentration into the water column will get lower with the use of activated carbon. If the carbon is left in the aquarium for a period of time, the chelated compounds in aquariums slowly decay and release their metals.

However not all trace elements are chelated, for instance SeaChem Flourish uses water soluble non-chelated iron, as well mineral blocks such as Wonder Shells are non chelated and any possible absorbed trace minerals are rapidly replaced by the Wonder Shell (which although mineral depletion by activated carbon is low, the use of Wonder Shells in aquariums/ponds utilizing activated carbon insures adequate minerals)

The use of Activated Carbon with Marine Protein Skimmers:
Although conclusive tests are forth coming, there is evidence that the use of activated carbon can limit the amount of foam refraction generated by a marine protein skimmer. This is likely due to the adsorption of Foaming Agents (MBAS) by activated carbon.
This presents a problem for many reef keepers since both carbon and protein skimmers are useful aspects of a complete marine filtration system.
My suggestion is to limit carbon use in cleaning filters run during certain times of the day (or week), especially after heavy feeding.

*A final concern with activated carbon is the possible release of contaminants after they have been initially adsorbed. This action is known as desorption or dumping. This could occur if other ambient water quality characteristics change.
Although at the time of writing this article, I have not discovered the exact mechanism for causing this, but I do know that a tank that is not stable in its general chemistry, whether pH or Redox is a candidate for this possible problem of carbon use.


Here is a list of compounds carbon can or cannot absorb.

Please note that some compounds may be desirable to remove depending upon your tank requirements while the same compound may not be desirable in another aquarium environment. A good example would be tannins (which carbon removes reasonably well); in a soft water environment an aquarist would likely want to restrict the use of Activated Carbon, while someone keeping “dirty” goldfish may find the use of carbon on a regular basis (in higher quantities) a necessity.

WHAT CARBON CAN ABSORB:
Excellent Absorption:	Fair/Good Absorption	WHAT CARBON CANNOT ABSORB (or absorption is poor)
*Amyl Acetate *Amyl Alcohol *Benzene *Bleach *Butyl Alcohol *Butyl Acetate *Calcium Hypochlorite *ORGANIC carbon *Chloral *Chloroform *Chlorine *Chlorobenzene *Chlorophenol *Cresol *Defoliants *Diesel Fuel *Dissolved Organic Compounds *Dyes (such as Methylene Blue) *Ethyl Acetate *Ethyl Acrylate *Foaming Agents (MBAS) *Gasoline *Glycols *Herbicides *Hydrogen Peroxide *Hypochlorous Acid *Insecticides *Iodine *Isopropyl Acetate *Isopropyl Alcohol *Ketones *Methyl Bromide *Methyl Ethyl Ketone *Naptha *Nitrobenzene *Nitroluene *Odors (general) *Oil - dissolved *Organic Esters *Oxalic Acid *Oxygen *PCB's *Pesticides *Phenol *Sodium Hypochlorite *Toluidine *Trichlorethylene *Turpentine *Xylene	*Acetaldehde *Acetone *Alcohols *Antifreeze *Chloramine (only the Chlorine, zeolite needed for remaining ammonia) *Calcium Hypochlorite *Chlorophyll *Citric Acid *EDTA (an organic chelator of metals such as iron) *Ethyl Alcohol *Ethyl Amine *Ethyl Chloride *Etyl Ether *Lactic Acid *Mercaptans *Methyl Acetate *Methyl Alcohol *Methyl Chloride *Organic Acids *Organic Salts *Ozone *Potassium Permanganate *Propioc Acid *Propyl Acetate *Propyl Alcohol *Propyl Chloride *Radon *Solvents *Sulphonated Oils *Tannins (such as Indian Almond Leaf extract) *Tar Emulsion *Tartaric Acid *Xanthophyll	*Alkalinity *Calcium *Carbon Dioxide *Fluoride, *Formaldehyde *Hardness. *Lime *Magnesium *Manganese *Microbes, *Molybdenum *Nitrates, nitrites, ammonia *Phosphates *Selenium *Sodium, *Lead, Iron and other heavy metals are removed only by adding a chelation process using EDTA, an organic carbon molecule (then these metals can be readily removed)

References

*http://www.ci.epping.nh.us/MTBE%20Water%20Supply%20Engineering%20Fact%20Sheet.htm
*Activated Carbon For Pure Water
*http://www.ag.ndsu.edu/pubs/h2oqual/watsys/ae1029w.htm
*The Krib; Activated Carbon
*http://www2.hawaii.edu/~delbeek/reefaq3.html
*http://cnsi.ctrl.ucla.edu/nanoscience/pages/waterFilt-teach
* http://infotrek.er.usgs.gov/

Fish Baths/Dips for supplemental (& even primary) treatment of Bacterial infections, wounds, sores, Fungus (Saprolegnia), parasite infestations & more
Updated 11/06/09


Although the Article; Aquarium Disease Prevention has a relatively in depth explanation of how to perform (& why) a fish bath or dip, this Aquarium Answers post/article will hopefully expand more on this subject for a better understanding. I am also including input from members of Everything Aquatic Forum to further assist in this article.

The basic ingredients of a bath include:

• Salt (Sodium Chloride)
• Methylene Blue (this can be substituted with Potassium Permanganate in certain instances)
• Occasionally Epson Salts (Magnesium sulfate) can be used as well
• Further medications can be added (this will be addressed later in this article)

What is a bath or dip used for in the treatment of fish diseases or similar?

• Treatment of sores or injuries, especially open sores that expose deeper tissues (often minor injuries do not require a bath/dip). The Methylene Blue will stain tissues and aid in prevention of bacterial growth, as well Methylene Blue will increase available oxygen to tissues. Swabbing (or dripping) the wound, sore, or red streaks (caused by Septicemia) with Methylene Blue prior to a bath often increases the effectiveness.
• As an Aid to Ich, Velvet and similar parasite infections. Although a bath or dip is not an effective cure for in tank Ich infestations or similar, a bath/dip can increase survivability in severe cases as the bath/dip provides critically needed oxygen to gills/tissues (via the Methylene Blue), as well Methylene Blue will often stain the parasite on the fish and weaken it severely (keep in mind that Methylene Blue was used as an early Malaria treatment, and that Malaria is a protozoan as is Ich and Velvet). The use of baths/dips with sensitive fish such as Clown Loaches is often a must in my experience for moderate to severe Ich (Ichthyophthirius) infestations.
• As an aid to bacterial infections (such as Columnaris) or Saprolegnia (Fungus). As with wounds/sore, swabbing or dripping the Methylene Blue directly on areas of infection greatly increases effectiveness.
• As an aid to and for treatment of osmoregulation problems in fish such as Bloating and even Dropsy.
• As an aid to ammonia/nitrite poisoning, often as the result of poor handling/shipping and over crowded condition prior to an aquarist obtain a new fish. The Methylene Blue with be absorbed into the blood, kidneys, and liver where is can help lessens the effect of ammonia and nitrite poisoning.

What is better; a Bath or Dip?
This is a subjective question that can not be simply answered however I will give some generalizations.
A properly performed bath is much less stressful to the fish (the most stressful part is capture of the fish which can minimized with a breeder/holding net or proper netting). In fact I have seen fish bounce back from baths within a hour.
So with this in mind a mild to moderate infection or for many quarantine purposes the bath is the better choice. As well almost any injury is better treated with a bath since stress is a major factor with an injury. I often use baths over in tank treatments where “tank wide infections” are not present so as to not interfere with the biology of the aquatic environment in any way.

A dip is often a choice of last resort for seriously ill fish, especially with Dropsy, bladder infections or other infections causing osmoregulation problems.
One exception for healthy fish where I often choose a dip over a bath is for the prevention of Ich, Cryptocaryon, Oodinium and similar parasite infections. I have not seen a healthy fish ever succumb from a dip when used for this purpose and a dip is nearly 100% effective for such prevention in marine fish, somewhat less for freshwater (provided there is not latent infection already in the aquarium).
A dip is NOT a good choice for seriously injured fish or fish that have considerable open tissue due to infection, as the dip will often make this worse by extracting necessary body fluids that are already being lost. For these fish, the bath is the vastly better choice.


Performing a Fish Bath (expanded from Aquarium Disease Prevention);

A bath can be performed in as little as 1 quart of water (or even less) or in a 1 gallon Rubbermaid (or similar) container or a small BARE tank (not gravel, décor though). I generally use a 1 quart pitcher with ½ teaspoon of salt and several drops of MB (I also recommend rubber gloves and old towels, rags, paper, etc spread around since Methylene Blue is messy and stains).

For freshwater I would add Methylene Blue at double normal tank treatment strength (as per bottle instructions) then add salt (NaCl) at about 1 teaspoon per gallon (Epsom Salts can also be uses at 1/4 teaspoon per gallon in baths used for treatment, especially in cases of bloat, water retention, selling, etc.).
The salt (regular salt; NaCl) can be increased for difficult treatments, especially with salt tolerant fish such as livebearers (it is best to slowly add dissolved salt to increase levels gently in salt amounts over 3 teaspoons per gallon, even in salt tolerant fish).
Generally for most fish (even catfish based on University of Florida studies) 2 teaspoons per gallon can be tolerated for up to 30 minutes (many fish can tolerate 4 teaspoons per gallon), although if unsure about your fish’ tolerance, gradually add the salt via a dissolved solution during the first half of the bath.

A few more tips:
• I also recommend keeping the “bath” container in a location that does not allow the temperature to drop more than 2 degrees during this time so as to prevent shock when transferred back to the holding/display tank.
• If at all possible I recommend keeping the fish that are being given baths in a Breeder Net Box (see picture) or similar in the tank or in another filtered bare tank so as to make capture easy and less stressful for both you and the fish (if too much stress is incurred capturing the fish for each bath, this can negate the positive effects of the bath).
• ALL baths should start with water from the fish’ holding tanks water, so as to avoid pH and temperature shock. As well, ALL baths should have fresh Methylene Blue, salt & other medications if used, otherwise many medications can and will degrade and be less effective or even toxic in some cases.
The bottom line here is to throw away all bath water after completion of each and every bath.
• Floating pre-made fish bags of the dip water (with salt and Methylene Blue, do not add medications until immediate use) can make the bath process easier as everything is ready to go when you may be in a hurry. As well this allows for the correct water temperature.
• Although most bottles of Methylene Blue do not come with a dropper any more, I recommend finding a dropper that will fit the bottle or use an eye dropper so as to limit MB stains/mess.
• I generally do not recommend baths for larger fish (unless you are sure of your fish handling abilities), such as over 6-8 inches (15- 20 cm.), as often handling of these fish can be difficult and cause quite a mess. As well larger fish can be more easily injured due to the difficulty in handling them.
However, if a larger fish is in poor condition and question arises that the fish is already in a severely weakened condition, a bath or better, a dip may be attempted (see below for more about “dips”)

For saltwater I would add Methylene Blue at double normal tank treatment strength the Dilute the saltwater to 1.015 to 1.009, making sure your pH stays up by adding any buffers necessary before adding fish (1.009 is a must for Cryptocaryon prevention/removal).
The purpose of adding or lowering salt (whether SW or FW) is to change osmotic pressure which is an aid to parasite removal as most parasites such as Ich or Cryptocaryon cannot tolerate these changes as well as fish.

Please see the video at the end of this article for more help in understanding the process of a fish bath

Further Bath Tips from Everything Aquatic Member Fishfever

1. Always spread out an absorbent mat around the tank before doing anything to catch drips (and especially Methylene Blue, ***IT REALLY STAINS IF IT GETS ON ANYTHING ***). Gloves are good too to avoid the blue finger syndrome!

2. Premixing the salt with tank water in a large container saves time if you plan to give a number of baths. You could probably premix the MB also (not sure) but would not mix Potassium Permanganate since it reacts with tank water (I think it removes dissolved organic compounds in the tank water). I use an eyedropper to get the proper fraction of a teaspoon to gallon ratio for the Potassium Permanganate in the small bath container or double bag (it's not a perfect ratio but it's consistent).

3. If possible, give your bath in a container or double bags within the tank. This way the bath stays heated to the same temperature as the tank and if the fish jump they just jump into the tank. I fill my bath container or double bags just enough so they still float and the buoyancy pushes the container up against the rim and top cover, keeping it from trying to flip over. If you overfill the bath container will sink. Remember to float the bath container or bags in your tank long enough to equalize temperatures.

4. Since I have to give twice daily baths, I leave the fish in a small breeder net (about 6"x6"x4") overnight after the evening bath which I do just before I shut the tank light out and go to bed. This saves me from having to catch the fish for the morning bath, i.e. only have to catch her once a day for the evening bath.

Bath/Dip Risks

Obviously there are risks in the performance of a fish bath or dip, however in fish less than 6 inches these can often be minimized as per previously suggested tips.
For minor injuries or infections sometimes the risk of stress is simply not worth the bath, HOWEVER in my experience with literally 100s (if not 1000s) of baths/dips the risks for most applications is far less than the alternative. Even with extreme freshwater dips for saltwater fish, whereby the fish will react as if they are dead, the fish will generally “snap out of it” in a matter of hours and will be better than before this dip. Most baths are much less stressful than the previous example, so any observed stress will pass quickly if the bath is performed correctly.
As well in many cases such as sores or diseases, the use of a bath will allow for a more mild in tank treatment which is quite bluntly better for long term aquarium health than dumping in “tons” of harsh medications (especially when a hospital/treatment tank is not available).
The bottom line is to not let the bath/dip stress you more than the fish, as this procedure can often mean the difference of a successful treatment and an unsuccessful treatment especially in severe cases of Ich (this is especially true with sensitive fish such as Loaches) or in often difficult to treat bacterial infections such as Columnaris.

Medications in Baths; Another option to baths is (IN ADDITION to the salts and Methylene Blue, but NOT combined with Potassium Permanganate), you can safely add many antibiotics at double normal recommended dose for the 30 minute bath, this can both increase the effectiveness of the bath and the antibiotic added.

Medications that generally are good choices for baths are;

* Metronidazole which is s good choice for intestinal infections since it is not readily absorbed through the intestines.
* Kanaplex OR Minocyline for Columnaris, Dropsy.
* Nitrofurazone for Aeromonas or Furunculosis
* Usnea is an experimental alternative that has similar properties to Metronidazole and can also be effective for some viruses and possibly tumors. I use about 1 tablespoon per 6 oz. preparation for a 1 quart bath.
Please see this article for more about Aquarium Medications: “Aquarium Medications/Treatments; How they work”

Alternative to Methylene Blue

Potassium Permanganate can be substituted for Methylene Blue for treatment baths for ailments such as Flukes, cloudy eyes, & some parasite and bacterial infections such as Columnaris (generally Potassium Permanganate is the better choice for Columnaris unless the fish is displaying rapid breathing or is on "death's door").
HOWEVER for "pure" preventative baths, ammonia poisoning or unknown problems, Methylene Blue is by far the better choice.

See this article under Potassium Permanganate or Methylene Blue for more: Aquarium Medications; Chemical Treatments.
Another key point is that Methylene Blue can quite SAFELY be overdosed as it takes high amounts with long term exposure to be toxic, while Potassium Permanganate should never be overdosed.

Cautions About the Use of Potassium Permanganate for Baths/Painting Infections:

Since Potassium Permanganate is strong oxidizer, caution should be exercised in usage for baths and especially as direct application for external infections (unlike Methylene Blue which is very difficult to over dose). For most fish, a double dose of the normal in tank recommended dosage. This varies from product to product, however using Jungle Clear Water as an example; the recommended tank dosage is 5 mL per ten gallons, so the bath dosage would be 10 mL per ten gallons (or 5 mL per 5 gallons of “bath” water).
Fish such as many Tetras, Loaches, and similar “sensitive” fish should be given consideration in dosage of Potassium Permanganate.

An even more important consideration is the use of Potassium Permanganate for direct application/swabbing of certain infections such as external symptoms of Columnaris (see the next section for more about swabbing/dips). Potassium Permanganate should be diluted at least 3/1 (water/PP) for this use and often more so depending upon the fish in question (testing on a healthy part of the fish in question or a related fish may help determine tolerance). As well do Not use even diluted PP anywhere near the gills of a fish.
Please note that this point of dilution does Not apply to Methylene Blue which is safe to use full strength, even around gills (although internal gill application is best performed via a bath, not a swab).

Dips, Swabbing, etc.

For known problems (or sometimes as a preventative for new fish from questionable sources) a 3-5 minute dip is sometimes even more effective (albeit more stressful to the fish). In a dip, I again adjust pH and add Methylene Blue, however in the case of the marine fish, I will use a specific gravity of 1.001 for the saltwater fish and a specific gravity of 1.012 of 1.015 for the freshwater fish (2.3 oz. or approximately ¼ cup of fine salt per gallon). This dip should be no less than 3 minutes and no more than 5 minutes to be effective.
To lower the stress a high salt dip for freshwater fish or a freshwater dip for marine fish it is advisable to use the first 2 minutes (of a 5 minute dip) slowly introducing the saltwater (or freshwater for marine fish) until the fish is in the desired salinity water for the remaining 3 minutes.
Make sure that the water added slowly during the first 2 minutes is premixed with salt prior to use for freshwater fish or pre-adjusted for pH for marine fish.

A dip is often a better choice than a bath for a large or otherwise “spastic” fish due to the much shorter duration. As well a dip, albeit much more harsh than a bath (when used as described), may be a better choice for a very ill fish that may be “at deaths door” and the risks of a dip are low when compared to the fact of the probable imminent death of the fish anyway.
A dip is also a good choice for problems that stem from fluid build-up and poor osmotic function, such as many causes of “Pop-Eye”.

*I also use dips to replace quarantine when not possible for fish of questionable sources; especially with marine fish as a dip is nearly 100% effective for destroying Oodinium or Cryptocaryon on marine fish (the osmotic pressure causes the parasite cells to burst). Keep in mind that the dip does not destroy these parasites in the water column if the disease has already been accidentally introduced.

*Another similar idea is to directly drop or “paint” with a Q-Tip (or similar implement) Methylene Blue, Potassium Permanganate, or Hydrogen Peroxide onto a problem area such as Saprolegnia/fungus, Columnaris, or similar. This can be VERY effective for stubborn external infected areas on a fish.
Potassium Permanganate & Hydrogen Peroxide are generally more effective for the above noted infections (but also should be diluted, unlike Methylene Blue), however sores, wounds, and in particular gill problems should Not use either Potassium Permanganate or Hydrogen Peroxide, rather Methylene Blue is a vastly better choice (again especially for direct gill applications where PP will burn the gills and often kill the fish as a consequence).

The use of Methylene Blue as a swab, dip, and to a lesser degree a bath will also expose healthy or at least normal tissue as Methylene Blue will generally adhere to infected areas or wounds staining the area “blue” due to the lack of the normal “slime” coating fish have on healthy areas of a fish’ epidermis. Even scar tissue will generally not stain “blue”, so this a good test of whether or not a “growth/sore” is actually an infection or similar (please note that some cancers/tumors can mimic healthy tissue and not stain blue).

A FEW HELPFUL CONVERSIONS
(Use accurate teaspoons, not silverware):
*Teaspoon = 4.929 mL
*Tablespoon = .5 fl. oz. = 14.787 mL
*For mixing salt for a dip; 1/2 dry cup will make a specific gravity of about 1.023- 1.025; For 1.015 specific gravity for a dip, use approximately 1/4 to 1/3 dry cup.

Fish Bath Video;

Streptococcus aerobic gram positive bacterial infections in aquariums, Eye Infections
Updated 1/09/10


This article deal with the most common gram positive bacterial infection affecting fish; Streptococcus iniae, and agalactiae as well as closely related bacterial groups; Lactococcus , Enterococcus , and Vagococcus.

The most common symptom these bacteria will show as is cloudy eyes and although by a large majority most aquarium bacterial infestations are gram negative, most eye infections are generally gram positive and caused by Streptococcus or related bacterium

Occasionally Aeromonas in freshwater or Vibrio in saltwater will show up as eye infections, especially in “Pop Eye” and in this case following treatment for the gram negative anaerobic bacteria that Aeromonas and Vibrio are is recommended.
Please see this article for more: Treatment and Identification of Aeromonas and Vibrio in Aquariums and Ponds

Although “Cloudy Eyes” (corneal opacity-whitish eyes) is the most common symptom of these gram positive infections, other symptoms are possible such as:
*"pop-eye" (though usually caused by Aeromonas),
*hemorrhages in or around the eye,
*a “milky” slime,
*erratic swimming,
*swim bladder issues (inability to regulate buoyancy) & lethargy;
*darkening of body (such as a “black moldy appearance, although this is NOT a true mold/Saprolegnia), the gill plate, base of the fins, vent/anus, or elsewhere on the body.
On rare occasions Streptococcus may be a cause of Dropsy. As well some cases of “False Neon Tetra Disease” (FNT) may also be caused by Streptococcus.
Often fish with Streptococcus iniae infections will not eat, which can complicate treatment for this bacterium when it is internal, especially for freshwater fish which do not drink water they are contained in (unlike most marine fish).

Most bacterial diseases of fish are opportunistic (such as Aeromonas or Columnaris), Streptococcus, on the other hand, does not seem to be a truly opportunistic pathogen, as it can be more aggressive than many other environmental bacteria. In one experimental study (Ferguson et al. 1994), populations of zebra danios and white clouds exposed to high concentrations of Streptococcus in the water experienced 100% mortality within 2-4 days of exposure. For this reason it is important that Streptococcus infections be quickly identified and managed to prevent major losses.

It is also noteworthy that recent studies have also shown growing incidents of this bacterial infection in fish farming (which is where most of the research into Streptococcus in fish is made available from). In fact this problem has become severe enough among Tilapia and Trout farms that a vaccine is now in the testing phase for Streptococcus iniae.
Fish that have been documented most susceptible (this does NOT mean other fish cannot get this bacterial pathogen) include rainbow sharks, red-tailed black sharks, rosy barbs, danios, and some tetras and some cichlids.

Treatment

For most “full blown” Streptococcus infections (not necessarily a mild eye infection), Erythromycin is often the drug of choice. Mortality should cease within 48 hr of treatment with the correct antibiotic if complicating factors are not present. If the disease is internal therapy may be difficult because erythromycin does not absorb well, and this case treatment with Neomycin “lased” foods is recommended.

It should be noted that although Erythromycin is the drug of choice, because it is an effective anti gram positive bacterium medication, it is also very hard on nitrifying bacteria, so having cultured sponge filters or other “seasoned” filter media to replace during and/or after treatment is very important since this although Streptococcus is not opportunistic, many opportunistic bacterium such as Columnaris may follow, especially if ammonia/nitrites rise during or after treatment.
Although generally the antibiotic of choice, sometimes Streptococcus bacterium can build a resistance to this antibiotic (as well sometimes destruction of tank environment from the use of Erythromycin can be a double edged sword that renders this antibiotic ineffective especially if tank conditions are not closely monitored). In this case, Tetracycline Hydrochloride may be a good substitute. Tetracycline is not without its side effects either and its use can severely lower red blood cell counts in fish, so increasing circulation is a must. As well it also is hard on nitrifying bacteria and tends to cause a buildup of brown foam and should never be combined with Erythromycin.

Other potential treatments include combinations of Erythromycin and Nitrofurazone (Furan 2); Kanacyn combined with Nitrofurazone (Furan 2) (Nitrofurazone is especially useful for topical infections that may show as a milky slime) or Neomycin (in food for suspected internal infections); Minocycline in the same combinations in place of Kanacyn. The advantage of possibly using Kanacyn is that this medication can also prevent/treat opportunistic Columnaris or Aeromonas infections that may arise.

Melafix is a good preventative treatment and may be effective for mild or even moderate Streptococcus infections. Sometimes for very mild eye infections (no other symptoms) Melafix is the only treatment you may need to use.

If eyes are directly affected (and the only primary target of this infection), removing the fish add treating the fish directly in the eyes with Silver Nitrate followed by Potassium Dichromate is extremely effective, the only problem being is that Silver Nitrate is hard to find, although sometimes photo lab supply businesses may have this. Potassium Permanganate is reasonable second choice for this direct eye application and Methylene Blue a third choice for direct application.
Either way, sometimes the only “in tank treatment” that may have to followed up with when the eyes are treated directly is Melafix (used in the main tank or hospital tank, not in a bath).

Medicated Baths may also be a useful part of treatment for external Streptococcus infections in fish. These would be twice daily for 30-45 minutes and I recommend the use of Methylene Blue combined with a double dose of Erythromycin or Tetracycline, or even Usnea

If you suspect that you have a group of fish with a Streptococcus infection, the affected population should be isolated from all others. If possible, have dedicated equipment (nets, siphon hoses) for these fish.

Prevention

Since Streptococcus is not as opportunistic as discussed earlier, prevention is VERY key to stopping this bacterium. This would include medicated baths or quarantine of ALL new fish (see this article: “Aquarium Disease Prevention”), and if at all possible “UV Sterilization”,
Although Streptococcus does seem to occur more frequently at warmer temperatures, it can occur at any time of the year. Studies in marine systems in Japan ( Kitao et al. 1979) indicate that Strep may be present in salt water and mud, with higher incidences in the water during summer months.

Nets, siphon hoses, vacuums, etc should ALL be soaked in Potassium Permanganate (or even bleach) prior to use in other tanks if you have more than one aquarium.

Use of anti-septic treatments such as Melafix, especially after injury or similar is helpful for prevention or even treatment early in Streptococcus infections. Think of it this way, many human infections (including Staph) are common and simple treatments with products such as Neosporin is all that is necessary in minor injuries to prevent a major infection. Although Melafix has little or NO anti gram negative bacterial abilities, it is an excellent preventive even for diseases such as Columnaris from getting a “foothold” by killing off disease pathogens such as Streptococcus that may be followed by Columnaris.

Are you looking for an informative and friendly Aquarium Forum to help with your fish problems (or simply to share your experience)? Consider this forum with a friendly family atmosphere: Everything Aquatic Aquarium Forum

References:
http://edis.ifas.ufl.edu/FA057
http://www-csgc.ucsd.edu/NEWSROOM/NEWSRELEASES/2008/Victor_Nizet.html
http://www.thefishsite.com/articles/190/streptococcus-in-tilapia

Copyright Carl Strohmeyer 1/27/09

This Page/Post is designed as an alternative directory of articles here at Aquarium Answers (we also provide the list of articles in the right navigation bar on every post/article that is set in chronological order)

This page is set up by topic

TOPICS

AQUARIUM CHEMISTRY:

*Hydrogen Sulfides- Hydrogen Sulfide production in anaerobic De-Nitrification for Aquarium/Pond Nitrate Removal

*Salt in Freshwater Aquariums- The use of Sodium Chloride more commonly known as just plain salt seems to be a constant source of controversy among aquarists. This article deals with the known facts and myths about the use of salt in FW Aquariums.

*Aquarium Nitrates- Although less toxic than ammonia and nitrite; nitrate (NO3) as a nitrogen compound also causes stress at all levels making a fish’s organs work harder to adjust to it’s new environment, especially at levels higher than 100 ppm)

*What should I know about tap water for my aquarium. From Chlorine and Chloramines to Phosphates -Regularly updated information about the use of tap water in aquariums as well as removal of toxic elements there in.

*PROPER OSMOTIC FUNCTION- ELECTROLYTES; How do Fish Drink- One of my more in depth and most updated articles dealing with often forgotten yet important subject of aquatic osmoregulation.

*AQUARIUM TEST KITS; what they are used for and their importance- Aquarium/pond Test kit basics and what they should be used for as well as general water parameters to achieve with your test kits.

*The use of plaster of Paris in Ponds/Aquariums- This article deals with poor chemical comparisons to mineral block (such as Wonder Shells) and Plaster of Paris (as perpetuated in some backward forum posts). Also the article contrasts the chemical composition of the ocean

AQUARIUM DISEASES, TREATMENTS AND SIMILAR

*Streptococcus gram positive bacterial infections in aquariums, Eye Infections

*Fish Baths/Dips- Fish Baths/Dips for supplemental (& even primary) treatment of Bacterial infections, wounds, sores, Fungus (Saprolegnia), parasite infestations, poisoning & more.

*HITH; Hole in the Head Disease in Fish- Information that is regularly updated about this often controversial disease/syndrome that afflicts Cichlids in particular.

*Ichthyophonus in fish- Ichthyophonus (Ichthyphonus) fungi are one of the more devastating aquarium diseases. It is nearly impossible to treat, however it is easier to prevent.

*Fish Parasites, Detritus Worms, Feeding Worms - information about Trematodes and Nematodes in Fish as well as Detritus Worms, planaria, and feeding worms such as Grindal Worms.

*Angelfish Virus/Aids- Although not as common as in the 1990s, this viral infection can devestate an angelfish population (& potentially other fish)

*NEON TETRA DISEASE (Identification, prevention and possible treatment of) -Information about a fish disease that is often is often a catch all name for diseases of Neon Tetras specifically and many other fish as well.

*FRESHWATER VELVET - Piscinoodinium pillulare (also known as oodinium)- Also Information about Costia (Ichtyobodo)

*USNEA; USING USNIC ACID AS A FISH REMEDY -How Usnic acid and Mucilage which are both found in Usnea lichen can be used as effective alternative aquarium and pond fish treatments.

*What is a lateral line in fish? The functions and diseases of the lateral line. - Information about Head and Lateral Line Erosion (HLLE) which affects primarily marine fish

*DROPSY in fish -prevention, causes, and possible treatment of this malady that is often a symptom of other problems

*Fish Anatomy- This Aquarium Answers Post is simply for fish fin and fish anatomy identification


AQUARIUM FILTER MEDIA, CONDITIONERS, SIMILAR

*Aquarium & Pond Filter Media; types, capacities and more- In this article I will discus three basic filter media types and subtypes of these.
These filter media types are Mechanical (such as Micron), Biological (Such as Ceramic Bio Media), and Chemical (such as Carbon).

*AQUARIUM (& Pond) WATER CONDITIONERS - their ingredients (where available), what chemical functions they perform and uses based on my opinions of each based on using these products in a professional capacity as well as tests and available research.

*Activated Carbon- The pros and cons of carbon use; what carbon can and cannot remove and much more


AQUARIUM & POND FILTERS, PUMPS, & OTHER EQUIPMENT

*Marine (Saltwater) Aquarium Protein Skimmers- Useful opinions about Protein Skimmers based on mine and other aquarium maintenance professionals experience.

*Aquarium and Pond Pump, Power Head Review- Useful opinions about pumps (power head, propeller, etc.) based on mine and other aquarium maintenance professionals experience.

*AQUARIUM HEATERS- Types of Aquarium Heaters, how they work, temperature guide for selecting heaters, as well general care/information.

*POND VEGGIE (PLANT FILTERS)- The four basic types of veggie filters and how to install them, based on many years experience using this method (long before it became a fad)

*Do Bio Wheels Really Work- An excellent fact based study of the often over hyped Bio Wheel.

FISH CARE, HELP, BASICS, ALGAE & MORE

*Basics of Shipping Fish- Tips and basics about shipping, Problems to be aware of, Methods and products.

*Aquarium Size, Fish Stunting- This article deals with often controversial subject where anecdotal information is most often treated as facts, such as the 1 inch per gallon rule. Regularly updated!

*Aquarium Moving- Opinions and methods for Aquarium moving based o many years experience moving aquariums both short and long distance. This article has some information in common with the Fish Shipping article.

*AQUARIUM ALGAE- Information about these algae: Brown Diatom Algae, Common Green Algae, Thread/Hair Algae, Marine Hair Algae, BBA/Black Brush Algae/Black Beard Algae/Red Algae, Cyanobacteria (Blue Green Algae)

*Blue green algae in aquariums (Cyanobacteria)- more in depth information that is regularly updated about Cyanobacteria.

*Betta Fish Wild Habitat & More - information about the natural habitat of the common Bettas and how it can relate to their care domestically.

*Keeping Mollies in Aquariums- Basics and water parameters for Keeping the popular molly fish in aquariums, including the importance of GH of salt.

*SEXING FISH -Basic information about sexing some freshwater fish for beginners (not an article for experts)

*Cyclops, Are these freshwater copepods dangerous in an Aquarium- Information about Cyclops and also Predatory Damselfly larvae that occasionally find their way into aquariums and especially ponds

GENERAL AQUARIUM/POND CARE INFORMATION

*CORRECT AQUARIUM SILICONE APPLICATIONS; What Silicone to use and what not to use, Aquarium Repair, Aquarium construction- Also DIY Aquarium Glass Thickness recommendations, repair video, and more.

*Aquarium Gravel/Substrate; including pictures - Aquatic substrate recommendations/basics.

Please see this Web site for vastly more articles that compliments this Aquarium Answers Website:


SUMMARY
As I also note at Aquarium & Pond Information although some of these articles/posts are more basic in nature, many are more in depth and require a thorough reading to fully understand and picking out snips without reading the full article may yield incomplete information.

A little background; when I first started writing these articles for the internet (something many of my clients asked for years), I made them VERY basic. My early feedback was rather harsh as many said it was "nothing special", then some who knew me better said that although they were still better than many in content due to less anecdotal information, they did not come close to the delivering the information they knew I could and that my constant research should be reflected. Many experts in SEO told me similar as well. So now, although some of the articles are still more basic and not all that unique, many however will have well researched information you will not find elsewhere in one location and this information is only best understood when read in full.

I will make my point as to why I feel it is so important that these articles be read in full and not in snips which can result in anecdotal or poor information dissemination;

"In the 1980s I was mentored by an Endocrinologist (MD) whom was also an avid fish keeper (mostly marine). He helped me much understand the ins and outs of medications and one time gave me an in depth medical article that he though had useful information that could be applied to fish as well. Much of the information was not readily easy to understand for me, so I skipped over many sections and gleaned the points I wanted.
Later I was making some points to the Dr. and he stopped me and said I was incorrect and if I had read the article in full, to which I replied, 'no'. He then said that there is no way I could understand this article without reading it in full and applying ALL the information contained there in".
My point is, often it is easy and unfortunately ALL too common in this hobby to read just what we want, and many web sites (such as about.com) are good at satisfying this basically lazy desire (of which I too have been guilty of), however this often leads to poor understandings of the subject or worse.

Labels: Aquarium Pond Answers Directory

Hydrogen Sulfide production in anaerobic De-Nitrification for Aquarium/Pond Nitrate Removal
Updated 12/07/09

Hydrogen Sulfide is unfortunately a bi-product of anaerobic de-nitrification, of which denitrification is an important aspect of keeping low nitrate levels in both salt and freshwater. This said, it is important to achieve de-nitrification without undo amounts of Hydrogen sulfide produced
The production of Hydrogen Sulfide in aquariums (both salt and even more so freshwater) is a controversial subject, often with unclear answers as to whether anaerobic de-nitrification is beneficial in freshwater due to the POSSIBLE production of Hydrogen Sulfide. The keyword is “possible” as in saltwater, you CAN have de-nitrification with no or low hydrogen sulfide production.

With the most current research (although admittedly not conclusive in my view), you CAN have anaerobic de-nitrification and NOT have dangerous levels of Hydrogen Sulfide produced in both fresh & saltwater. With healthy de-nitrification it is possible to have low nitrate levels below 20 ppm

Points to achieving De-Nitrification (removal of nitrates) without hydrogen sulfide production

• One study showed that even though sulfate reduction (the production of hydrogen sulfides from Nitrates/Sulfur) took place maximally at ¾ inch (1-2 cm) depth, free hydrogen sulfide was present only below a depth of 2-1/2 inches (6-7 cm), above which Fe++ (Iron) was available for precipitation as iron sulfides.
So with this study in mind, keeping your substrate sand bed mixed at depths deeper than 2.5 inches and/or minimally aerated can prevent this process. This will also allow for better de-nitrification (lower nitrate levels) as nitrate will be allowed to better permeate the deeper sand depths allowing for more nitrate reduction and less sulfur reduction.

• Care should be especially taken with Under Gravel Filters as these filters can allow much compaction of gravel when gravel is much over 2.5 inches, as well mulm/sludge can build up under the under gravel plates and the biggest risk is when the filter is shut down either manually or by a power filter as this decomposing mulm can quickly go sulfur reducing anaerobic and not only produce hydrogen sulfide, but the more immediate danger is a sudden decrease of dissolved oxygen levels from the die off of aerobic nitrifying bacteria trapped/dying in the deeper layers of gravel or under the plates.

• Along this same line of thought as the previous point, a good surface flow of water and correct vacuuming procedures which includes surface vacuuming of top layers of gravel (in marine tanks I recommend a ½ inch layer over the several inch deep bet of fine #00 oolite sand), AND as well occasional and gentle vacuuming of deeper layers except where plant roots would be damaged.
One test/study I read showed that organics in totally oxygen deprived test tubes made little difference in the production of hydrogen sulfides, HOWEVER it was the total lack of oxygen and nitrates in these layers that allow for sulfate reduction to start.

• Another study showed that when 300 ppb hydrogen sulfide was added to Biscayne Bay and Gulf Stream waters off of Florida, the half life of the sulfide was 49 and 147 minutes, respectively. Such studies found that sunlight (both ultraviolet and visible) was able to significantly accelerate the oxidation.
This speaks “loudly” for strong lighting whether it be healthy 6400 K SHO lamps or Metal Halide (which my previous notes in reef keeping showed NO hydrogen sulfide production when these lights were employed). This also shows one more reason why a UV Sterilizer should be used, whether fresh or saltwater if they can at all be afforded (of which UV Sterilizers are not all that expensive, even for good quality models such as the Terminator).

• In freshwater aquariums, plant roots have been shown to not only remove ammonia directly, but as well (and more importantly as to the subject of this article) prohibit the total anaerobic conditions that promote production of hydrogen sulfides

What these points show is that the hydrogen sulfide production in substrate is only common when the area of sulfate reduction in question is totally deprived of oxygen and nitrates. As long as very small amounts of oxygen and nitrates can penetrate into the substrate (or live rock), this will not become a problem. This same general idea holds true for man made de-nitrators that have no oxygen whatsoever and are not bathed in adequate nitrates.
Light energy has also been shown to be a factor in destroying rogue hydrogen sulfide molecules in the water and penetrating into some layers of substrate as well.

Appearance/Evidence of sulfate reduction
A tell-tale sign of Hydro Sulfide production is black areas in the deep areas of sand or substrate, whether freshwater, marine, or especially ponds. The rotten egg odor is another sign although as Hydrogen Sulfide levels in the air increase, research has shown that human’s olfactory senses tend to block out the smell.
Please see the picture to the left of what the "black" Hydrogen Sulfide producing layers look like in sand (click picture to enlarge).

Hydrogen sulfide is toxic to a wide range of organisms, including people, which is a FACT that has been known for many years. It is just now becoming clear, however, that hydrogen sulfide also appears to play important roles in normal biochemical processes in animals. Neurons and muscles, for example, may use it in various ways, but exactly how this takes place has not been made clear scientifically.
One way that hydrogen sulfide exerts its toxicity is by inhibiting a mitochondrial enzyme called cytochrome c oxidase. It can be inhibited at hydrogen sulfide levels in solution as low as 30 ppb.12 Such inhibition limits the ability of mitochondria to produce energy for cells. Another enzyme, catalase, is inhibited at concentrations of 6,000 ppb.12 Other mechanisms of toxicity are also likely, and have recently been studied.

Hydrogen sulfide eruptions happen frequently off the shore of Namibia because of patterns in the ocean currents called upwelling. In this region, cold water pushes nutrients from the ocean floor to the surface, where ocean life thrives. In particular, large colonies of microscopic ocean plants, phytoplankton, grow in the nutrient rich water, forming the dark green swirls seen in this image. As the plants use all of the nutrients, they die and sink to the sea floor where bacteria consume them. The bacteria release toxic hydrogen sulfide gas into the soil. Eventually, the toxic gas erupts from the soil. In addition to the bright waters seen by satellites, the event is marked by massive fish die-offs and a strong smell that resembles rotten eggs. To date, hydrogen sulfide eruptions have only been observed off the shore of Namibia
Please click the picture to the left to enlarge.

HOWEVER hydrogen sulfide toxicity problems aside, I have observed and the most up to date scientific evidence supports that an aquarist or pond keeper CAN maintain de-nitrification without the worriesome production of hydrogen sulfides

For Further information about the Aquarium/Pond Nitrogen Cycle, please see this very well researched article:
"The Aquarium & Pond Nitrogen Cycle"

Further references:
http://www.agu.org/pubs/crossref/1997.../96JD03817.shtml
http://www.fhsu.edu/biology/eastrauss/Courses/MicrobEcol/Papers/Gerhardt%20et%20al%202005%20Biogeochem.pdf
http://reefkeeping.com/issues/2005-12/rhf/index.php