Trematodes, Nematodes, Annelids, & Feeding Worms (Microworms, etc.) in Aquariums & Ponds (Flukes, Fish Lice and Internal Round Worms, Detritus Worms); 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 identified as Planaria). More about Detritus Worms further into the article.

Also many types of feeding worms; such Grindal Worms, Whiteworms, Walter Worms, Vinegar Eels, and Microworms.

TREMATODES:
(Flukes, Fish Lice)


The trematodes belong to the Animal Kingdom Phylum Platyhelminthes, the flatworms 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.

Internal Trematodes:

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:


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 this material being produced by the fish 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.

Common 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 flukes in Marine fish, please see this article:
Monogenean Parasites in Marine 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, hydro peroxide or even Neosporin followed by a 30 minute Methylene Blue bath


NEMATODES:
(Round Worms)


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.


A method of diagnosing a nematode problem is generally just a guess. When a fish is eating well yet is still not putting on weight, an intestinal infestation may be suspected. 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 more 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.
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.

A few common Nematodes:

Capillaria is a relatively common nematode that lives in the intestines of angelfish and discus (and other fish as well)

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 guppies, gar, danios, and angelfish. 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 (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)

TREATMENTS for internal Trematodes and Nematodes:

*Metronidazole
*Jungle Internal Parasite Guard (ingredients: Metronidazole, Praziquantel)
*Levamisol
*Piperazine
*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 such as may be witnessed in a white feces diagnosis where the aquarist is unsure of whether this is a worm or Aeromonas/Hexamita infection.

Treatments for external Flukes:
*Clout
*Trichlorfon
*Potassium Permanganate

Annelids “Segmented Worms” - Including:
DETRITUS WORMS

The annelids are the phylum of segmented worms which includes 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"), are in marine environments.
All the oligochaete worms are hermaphrodites (an organism that posses both male and female genitalia). Many are nearly microscopic too

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, however high numbers of particular species can indicate low oxygen levels and low filter productivity, which very often suggests some degree of pollution caused by poor cleaning procedures, over crowding, over feeding and poor filtration
Please reference these sources for even more identification (and further information so as to dispel the internet aquarium myth that these are Planaria):
Planaria
Aquatic Life: Worms ,
Oligochaeta Worms
Aquatic 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

Annelids:

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.

Grindal worms
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).









Nematodes


MicroWorms
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 Eels also 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.

References:
The Worms
Vinegar Eels
Whiteworms
Microworms (Panagrellus redivivus)
Diagnosis of Fish Poop
Introduction to Freshwater Fish Parasites: