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Aquarium, Pond Fish Parasites; Trematodes, Flatworms, Nematodes, Detritus, Anchor Worms
in Aquariums & Ponds
- Platyhelminthes (Flukes, Fish Lice, Flat worms, Planaria)
Basics, Identification, and TREATMENT in Aquarium and Pond Fish.
Information about non parasite DETRITUS WORMS (commonly seen when an aquarium is cleaned or in aquariums with high bio loads and is an area with much confusion especially on the internet and often mis-identified as PLANARIA (Freshwater)). More about Detritus Worms further into the article.
Also many types of feeding worms; such Grindal Worms, Whiteworms, Walter Worms, Vinegar Eels, and Microworms.
(Monogenea, Trematodes/Flukes, Planarians)
Platyhelminthes consists of the unsegmented flatworms, which include both free-living and parasitic species. They have bilateral symmetry, and can move by using layers of muscle or by gliding along a slime trail using cilia. Flatworms lack a circulatory system and complete digestive system, instead flatworms absorb nutrients through their skin and excrete wastes using specialized "flame cells". Flame cells function like a kidney, removing waste materials.
A few flatworms have primitive light-sensing "eyes" that allow them to move either towards or away from light, while other species have different types of sensors on their bodies, including chemical, balance, and water movement receptors. Most species of flatworms reproduce both sexually and asexually.
The trematodes belong to the Animal Kingdom Phylum Platyhelminthes, and are commonly referred to as flukes.
Trematodes usually have flattened bodies, a primitive digestive system, suckers for attachment to their hosts, and are hermaphrodites (an organism that possesses both male and female sex organs).
The Monogenea are the class ectoparasites that infect fish.
Planaria are both marine and freshwater and can be parasitic, but this is generally rare and the few that are, are generally toward corals, eggs or other stationary "victims".
Internal Flukes generally use intermediate hosts such as snails or other mollusks. The eggs must get into water in order to hatch and be able to infect their first host, a freshwater snail. The fluke develops in the snail and then burrows out to seek the second host which is a freshwater fish. Many species of snail and fish may carry these internal flukes.
- Here is a dissected fish displaying a serious internal Trematodes infection.
Gill flukes (Dactylogyrus) will appear on the gill filaments as tiny dark spots 0.04-0.08in (1-2mm) long.
Gill flukes can infect freshwater and saltwater fish and are found on fish from the wild as well as farmed fish. These parasites attach to the gills of the fish and feed on mucus, epithelial cells (cells that line the inside of gills and perform the tasks of secretion, absorption, protection, and transcellular transport), and blood from the host.
Much of the mucus being produced by the fish is in response to the physical injury caused by the parasites. Damage is physical and inflammatory, with secondary bacterial infections such as septicemia. Small or weak fish may die from the stress of acute infestations.
Gill flukes reproduce via eggs that drop away to hatch in about 2 to 4 days depending upon temperature.
The hatchling Dactylogyrus is ciliated similar to a paramecium. Once a host is found the water-borne Dactylogyrus larvae has eye spots that enable it to swim away from light and burrow into the fishes' gill cover as the fish respires.
In my experience in a healthy aquarium or pond, one or two fish in the aquarium/pond have a large enough parasite infection to be irritated.
If the larva fails to find a host, it dies.
However in poorly filtered and/or crowded ponds or in particular aquariums, these conditions increase the likelihood the larva will find a host. Once attached, it may take a week to mature and start producing eggs. The adult Gill Fluke is assumed to only live 5-10 days. Improving filtration and over crowding is as important as treatment.
With larger ponds, generally isolating the fish in a tub or small "play pool" is all that is necessary for treatment, assuming crowding and filtration is not a problem or improved.
Common aquarium carriers of gill flukes include: Plecostomus, Otocinclus, Corydoras, Koi, Discus, Characins, livebearers (Poeciliidae), some tetras (Characins) and Barbs (Cyprinidae), and Elephant Nose (Gnathonemus petersi).
For more about Monogeneans Flukes, which are a group of parasites best described as flatworms but are now considered a different class from Trematodes, please see these articles:
*Monogenean Parasites, Marine Fish
*Monogenean Parasites in Fish
FISH LICE (Argulus):
These are often round, flat and green.
They are similar in treatment to flukes and anchor worms. These can be physically removed with tweezers, and then the wound treated with Mebromin, hydrogen peroxide or even Neosporin followed by a 30 minute Methylene Blue bath
The Acoel flatworms commonly observed are “Redbugs” or “Red Planaria”, of which the genus Convolutriloba is a member as in the picture to the left of Convolutriloba retrogemma.
While Convolutriloba retrogemma are often blamed for coral attacks, in reality this is rare. Rather, they breed rapidly and reproduce either sexually, laying eggs or by the asexual processes of fission/ budding where the worm simply splits up, producing a bud that forms a new worm.
Therein lies the problem: the flatworms crawl along the coral in search of food and, as they rapidly multiply, they block the coral's light as well as hamper nematocyst capture of the coral’s prey. The coral is thus deprived of symbiotic nutrient nourishment, as well as planktonic food, and slowly starves to death.
A freshwater dip of corals or similar is the best prevention for these flatworms.
See also the section: Detritus Worms for more information about the confusion of detritus worms (annelids) with Planaria in freshwater aquariums as propagated by about.com.
Treatments for external Flukes or Worms (including Flatworms/ Planaria):
Clout and other "in tank" treatments are often more effective when accompanied by baths or dips, as well, if a parasite such as a camalanus worm is exposed, treatment is often more effective.
For marine applications, I generally will treat twice with a water change and carbon treatment in between. ALL invertebrates should be removed during treatment (Corals, Shrimp, Anemones, etc.).
Prior to re-introduction to the treated aquarium, all corals should be dipped in pH stabilized freshwater for 25 to 45 seconds. A standard dose of Potassium Permanganate or Clout can be added to this dip for extra measure.
This can also be used for nematodes, camalanus worms, or internal protozoans; although sometimes multiple dosages may be required.
This can be used as either a bath (as well as mixed with Methylene Blue) or 'in-tank. treatment.
This is highly effective when used as directed for external parasites
Mild effectiveness for internal parasites
*Tetra Parasite Clear
Nematodes, also known as Roundworms, are a very common phyla of animals of which there are many parasitic forms. Nematodes are one of the simplest animal groups to have a complete digestive system, with a separate orifice for food intake and waste excretion unlike the Trematodes mentioned above. Reproduction is usually sexual and males are usually smaller than females. Parasitic Nematodes can have quite complicated life cycles, moving between several different hosts or even locations in the host's body.
If the Nematode has a direct life cycle, then it does not need an intermediate host and infection can spread directly from one fish to another by means of a fish ingesting of eggs or larvae.
If the Nematode has an indirect life cycle the nematode eggs or larvae enter an invertebrate intermediate host (such as copepod, tubiflex worm, or insect larva) or a fish intermediate host (these fish are then consumed by larger carnivorous fish) prior to being eaten by or entering the final host fish.
Indications (Diagnosis) of Nematode Infestation:
A method of diagnosing a nematode problem is generally just a guess. This is particularly plausible when a fish is eating regularly yet continues to lose weight, metabolizing body musculature to stay alive. This is usually seen as thinning along the back on either side of the dorsal fin. This often results in a well-fed fish starving to death.
White feces can also be an identification tool, however this can be misleading as to a true Nematode (worm) infestation, as long thin white feces is just as often an indicator of a bacterial infection; generally Aeromonas. This can also be an indicator of a combination bacterial (again Aeromonas) and protozoan Flagellate infection, usually Hexamita.
Loss of appetite along with the other mentioned symptoms (such as thick white feces, along with some bloating on one side or both of the fish) can also be an indicator of a Nematode infection, especially a Eustrongylid nematode infestation.
Generally a more positive identification of internal Nematodes is a thread like worm protruding from the anus.
True identification begins with a microscope. Nematodes are smooth, cylindrical, relatively long worms, which distinguishes them from the flatter, segmented tapeworms and from the wider and shorter Monogenea Flukes.
Here is a list of some other general symptoms of nematode infections (besides the above already mentioned symptoms):
• Body Hemorrhaging
• Lumps or nodules on outer body (epidermis)
• Bloated abdomen (the fish may continue to eat or show otherwise normal behavior)
• Cysts, Inflammation, or Granulomas
A Few Common Nematodes:
Capillari is probably the most common nematode due to the relatively non-complex life cycle and ease of transmission, as Capillaria spread from one fish to another by ingestion of infective larvae that live in the intestines of cichlids such as angelfish, discus, gouramis, tetras, cyprinids (and some other fish as well). Symptoms common to this particular nematode include a bulge in the lower abdomen near the vent, or Capillari worms protruding from the anus.
Eustrongylid nematodes are found in muscle within the body cavity or encapsulated on the liver and other organs. These nematodes can affect a number of different species such as guppies, gar, danios, angelfish and other cichlids.
Affected fish typically have bloated abdomens (similar to dropsy of bacterial origin), as these nematodes often migrate into the body cavity and can be quite large. Unfortunately the treatment of these Nematodes usually fails due to the location of the larvae within the coelomic cavity or in the muscle of the fish (which is often misdiagnosed as bacterial Dropsy leading to the statements that “Dropsy is un-treatable”)
Camallanus Nematodes infect the gastrointestinal tract of live-bearers, cichlids and other species of freshwater fish. Usually, the first indication of infection is a red worm extending from the anus of a fish (sometimes mistaken for feces)
The life cycle of Camallanus worms passes through three phases, a free-living stage, a series of molts during which time the worms infect an intermediate host (crustaceans such as Cyclops and Gammarus) and then another molt that takes place in the final host/fish. If the intermediate host crustacean is eaten by a fish, then the third-stage larvae becomes active and will start feeding again. After two more molts, it will become a sexually mature male or female adult worms. These are the distinctive red worms aquarists see protruding from the vents of infected aquarium fish.
The life cycle of Camallanus worms passes through three phases, a free-living stage, a series of molts during which time the worms infect an intermediate host (crustaceans such as Cyclops and Gammarus) and then another molt that takes place in the final host/fish.
If the intermediate host crustacean is eaten by a fish, then the third-stage larvae becomes active and will start feeding again. After two more molts, it will become a sexually mature male or female adult worms. These are the distinctive red worms aquarists see protruding from the vents of infected aquarium fish.
TREATMENTS for Internal Trematodes and Nematodes:
*Metronidazole is a mild treatment, but it can be even more effective when combined with SeaChem ParaGuard
*Tetra/Jungle Parasite Clear
Parasite Clear can be used as a medicated fish food soak for internal parasites by using 1/2 tablet for an average 60 gallon bio load medicated fish preparation. Fish food should be soaked for 15 minutes.
After soak, pour entire contents into aquarium.
Additional medication can be added for a full tank treatment; for example with a 50 gallon aquarium, use 1/2 tablet in fish food soak and use the other half plus four more tablets in the aquarium.
API General Cure can also be used for this medicated fish food soak.
*Levamisol One of the most effective treatments for nematodes.
Most commonly available as Levamisol HCL which is slightly diluted of the active ingredient of Levimisol. See this article for use:
Aquatic Medications #3; chemical and parasite treatments
Treat with Levimisol once followed by a water change and treatment in 5-7 days. Treat a third time after 1-2 weeks following the second treatment.
Be careful, as Levamisol can kill many worms quickly, which with most internal nemtode infections is not an issue since they are not generally widespread. HOWEVER with use for widespread worm infestations, this can be a problem which is why this should NEVER be used to kill Detritus Worms (often misidentified as Planaria)
Here is a source for Levamisol:
*Combinations such as the above mentioned Jungle Parasite Guard that have Metronidazole as an ingredient as this medication is often effective for secondary bacterial infections such as Aeromonas and even better for possible Hexamita infestations of the gut, as witnessed in a white feces diagnosis where the aquarist is unsure of whether this is a worm or Aeromonas/Hexamita infection.
For BOTH Internal and External Nematode/Trematode Treatment
Medicated 30 minute baths using Methylene Blue, Aquarium Salts, as well as an antibiotic such as Metronidazole or Kananmycin (generally Metronidazole) at double normal recommended tank strength; This will aid in absorption of medications and osmoregulation that is VERY important, especially with internal parasite infestations which are difficult to treat even with strong medications. Methylene Blue will be absorbed and aid in oxygen delivery although it is only mildly effective against the parasites, Methylene Blue aids in the fish’ general health.
Salt is advised not only in the baths at 1-2 teaspoons per gallon, but also in the display or quarantine tank at 1 teaspoon per gallon to 1 tablespoon per 5 gallons as this will also aid in mucous generation and the movement of fluids inside the body cavity (osmoregulation).
Correct Calcium Levels are also important for osmoregulation that will aid the fish in “battling” a parasite infestation (especially internal).
See these article for more about medicated baths:
“Aquarium Disease Prevention; Section 9”
OR for even more in depth Fish Bath Help:
Fish Baths, Dips, Swabs; For Disease, Ammonia, etc. Treatment
Prevention is the BEST treatment for Nematodes, Marine Flatworms, and Flukes, especially Internal Nematodes This is accomplished by regular water changes, the purchase of fish from a known quality resource, removal of the final host (in the case of Eustrongylid nematodes; birds and pond sanitation), or any intermediate hosts (tubiflex worms or other oligochaetes).
It is noteworthy that many (if not most) fish farms are located OUTDOORS, so the spread of nematodes via intermediate and finals hosts is easier than one may think. Knowing your source for your pet fish is very helpful as often many internal nematodes will not show symptoms in fish for over 30 days after arrival in your aquarium.
A final note as to treatment of nematodes in particular is that nematode infestations are generally internal, making treatment and medication “delivery” very difficult. More so with Eustrongylid nematodes since they are found in difficult to deliver mediation internal body locations. My point here is, hopefully one can start treatment early or prevent an infestation altogether, however from my experience this is not a “real world” expectation as I have often failed to detect and treat with success (assuming it was treatable in the first place), so one should not be too hard on failures in treating internal Nematodes, as I have had my share of both successes and failures even under the good care.
Anchor Worms as seen to the left are a genus of copepod crustaceans (Species Lernea) that are parasitic to freshwater fish, especially coldwater fish often raised in ponds such as Goldfish.
I also have personally caught Trout that have been covered in Anchor Worms, but it is noteworthy that these trout were in a small,, man made lake that by late spring is too warm for Trout to live in.
The point about the trout is applicable to the many anchor worm infestations I have dealt with in goldfish, in that it was much more common in warm or warming months where water temperatures are higher than is best for goldfish; 80F or higher.
The Anchor Worm is not always noticeable as pictured here, often it starts out as a small red sore. These red sores then multiply followed by small thread like protrusions that are the anchor worm.
Other common symptoms include frequent rubbing/flashing, inflammation on the body of the fish, and generally lethargy of the fish such as sitting on the bottom or floating on the surface of the water.
Best treatment is to use tweezers to remove the worm from the fish. The fish should be gently cradled in the palm of your hand so as to not injure the fish as a net can. After removal, the wound SHOULD BE treated/swabbed with Methylene Blue (Best) or Hydrogen Peroxide.
If the Anchor Worm cannot be removed, this is especially true with very small anchor worms, a direct swab of 50% water Potassium Permanganate & water on the sore with the worm should be performed.
With either procedure, a bath should also follow that consists of Methylene Blue, Salt, Nitrofurazone, & possibly Metronidazole.
For serious infections and to prevent reinfestation, an in tank treatment with Clout (Dimilin is similar), or Tetra/Jungle Parasite Clear, or a ParaGuard/Furan 2 combination can be used (this is in order of strength).
A follow up in tank treatment with a Medicated Wonder Shell can be helpful too, regardless whether a previously mentioned strong in tank treatment was used or not.
Annelids “Segmented Worms” - Including:
The annelids are the phylum of segmented worms which include earthworms. Most annelids are NOT purely aquatic in fresh water; the annelids found in freshwater are all oligochaetes (which means "few-bristled") and are not very important in the freshwater ecology as are their marine cousins, the polychaetes (which means "multi-bristled").
All the oligochaete worms are hermaphrodites (an organism that posses both male and female genitalia) and many are nearly microscopic.
Detritus Worms (from the group of worms called Oligochaetes, sub group naidid worms) are often misidentified in the aquarium hobby as Planaria without close inspection by many internet articles such as about.com.
Many of these worms are accidentally introduced by live plants, gravel (especially in the case of common Detritus Worms) live fish foods, and even brought in with fish transfers.
(Click picture to enlarge)
Many not familiar with Detritus worms will label these as everything form midge larvae, Planaria to baby earthworms, of which none is true. They are very common and most often seen during vacuuming and other cleaning procedures.
These worms generally are not a problem often go un-noticed living in the gravel aiding in breakdown of wastes, however high numbers of particular species can indicate low oxygen levels, cloudy water, poor Redox and low filter productivity.
This very often suggests some degree of pollution caused by poor cleaning procedures, over crowding, over feeding and poor filtration.
When the population explodes these worms often leave the gravel and cling to the sides, usually close to the surface as oxygen depletion due to the cumulative affects of increased organic mulm (often resulting to pH.KH drops, higher nitrates, poor Redox Balance), cloudy water and simply too many Detritus worms drives them from the oxygen poor gravel where they normally hide/exist.
It is when these worms are crawling up the sides that most aquarium keepers take note, often not realizing that these worms have been present for some time living quietly in the aquarium substrate before a population explosion and often subsequent oxygen depletion drives them into the open.
Do NOT make the mistake of treating with Levamisol to rid your tank of Detritus Worms (aka false Planaria) as so many forums and websites advice. I know for a fact that the die off can kill off many fish and that simply taking care of the cause of the worm population "explosion" will remedy this issue!!!
Please reference these sources for even more identification (and further information so as to dispel the internet aquarium myth that these are Planaria):
Detritus Worms/Planaria in Aquariums
The above article is THE article to read on the subject!
Aquatic Life: Worms
“Detritus Worms" include these:
As stated earlier, control of these detritus (composting) worms is brought about by good vacuuming procedures, proper feeding, good filtration, lowering bio load, and addition of fish that will eat these.
This is a Planaria (a flat worm, not an Annelid)!
(click to enlarge)
WORMS USED AS FISH FOOD
Whiteworms (Enchytraeus albidus):
These are worms commonly used in feeding for larger fish; for instance, Gouramis and Cory cats love Whiteworms. Microworms (which are Nematodes not Annelids as are Whiteworms) are used for fry.
What we typically refer to as a "white worm" in the aquarium hobby is a segmented round worms (Annelids) that are closely related to the earthworm from the family enchytraeids. Whiteworms are an excellent food source for many amphibians and other aquatic creatures.
These worms can reach over 1 cm or more long. They are NOT a parasite danger to fish or other inhabitants of aquariums and are often seen wiggling up the sides or even at the surface. Whiteworms are basically a worm of de-composition and can multiply rapidly when over feeding is a problem. At this point the biggest danger is oxygen depletion from over population of these worms and a good vacuuming is in order. Many a customer has called or written me about these worms worrying that they have a parasite problem when in reality these worms are good for composting and are at worst an indicator of too much decomposing food and other organic debris.
A smaller version of White Worms are the popular Grindal Worms (which are also Annelids) often cultured as fish food (and named for a Swedish Aquarist).
All the worms that fall under the popular term of Microworms are Nematodes (roundworms) and include Vinegar Eels, and Walter Worms. Microworms (Panagrellus Redivivus) are non parasitic and small (0.5 - 1.5 mm.) worms, which make excellent supplementary live food for fry which are either too big for infusoria or have outgrown the infusoria stage.
Walter worms:Walter Worms are about half the size of the Microworm. These are recommended for feeding the very smallest fry. Walter worms generally live in the water longer than the Microworm.
For home grown Micro worms (Walter Worms) as well as Vinegar Eels, this is healthy source (the microworms are gut loaded with Spirulina): Over A Copper Moon Betta; Feeding Supplies
Vinegar Eelsalso a nematode are readily cultured in large numbers, provided certain procedures are followed. These worms (also nematodes) are a little smaller than micro-worms, a great size for most baby fish. The worms must be grown in natural cider vinegar that has not been chemically treated to inhibit the growth of bacteria or yeast upon which the worms feed. Advantages of Vinegar eels is they do not breath oxygen so don't create any problems in the fish tank, live a long time in the aquarium, and swim in the water column and stay towards the surface.
*Microworms (Panagrellus redivivus)
* Diagnosis of Fish Poop
* Introduction to Freshwater Fish Parasites
University of Florida; Nematode Infections in Fish
University of Florida; Fish Disease Diagnostic Laboratory Department of Zoology; University of Oklahoma
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