Capillaria (Nematode)

Capillaria are intestinal roundworms or nematodes and are unsegmented and round, usually long and transparent.

Capillarids reach one centimeter in length, and are thin and transparent. They have a hair-like thin shape, and can reach 3 cm in size, while only a fraction of a millimeter in width. They are a genus of nematode worms (roundworms). They live within the gut or liver of the fish. Only severe infections will affect the fish, so they may be present and undetected until water conditions deteriorate. Cichlids are especially susceptible to this parasite. The capillarids eggs are oval-shaped with a bulging plug-like structure (operculum) at each end. The eggs hatch into infective larvae.

Capillarids compete with the fish for nutrients, resulting in a fish that looks thin and emaciated despite having a healthy appetite.

Symptoms and Behavioral Signs
Healthy fish usually can resist this worm. Female guppies often succumb to after the stress of birthing. Emaciation and a loss of appetite.

Diagnosis
The feces may appear to be thin and white, or have light and dark segments. Live capillaria is rarely found in the feces. Eggs are usually present, even if the infestation is minor, as the capillaria produce prodigious amounts of eggs. The eggs are small, less than 50 micrometers. Although they can be seen at 200X magnification, they can be positively identified only under 400 to 600X magnification.

The best way to diagnose is to examine the feces under a microscope. The eggs look like they have been strong together and have the distinctive shape described above.

Note the eggs attached to each other like a string of beads.

Causative Condition
A recent introduction of an infected fish is the usual suspect. Live foods, such as daphnia, containing the eggs can be a source.

The worm has a direct life cycle, requiring no intermediate host. Fish become infected by consuming the capillarid's eggs while feeding on the bottom of the tank, where the eggs lie dormant. The guppy's digestive juices cause the egg to undergo development in the stomach, and it reaches maturity in the intestine.

Snails may store capillarid eggs.

Capillaria is opportunistic and will overcome a fish when its immune system is depressed.

Prevention and Treatment
Eggs can lie dormant at the bottom of the tank, so infected tanks should be bleached.

Fluke-Tabs have been reported as extremely effective at treating Capillaria sp Fluke-Tabs active ingredients are trichlorfon (an insecticide with anti-cholinergic activity) and mebendazole (anti-helminthic). Mebendazole prevents glucose uptake, killing both adults and embryos.

Treatment Regime

Follow the instructions provided in the treatment section of the library. The treatment should be repeated in 24 and 48 hours, with a 10% a day water change. Do a water change (or use carbon in the filter) after 76 hours to remove the drug from the tank.

Levamisole and Piperazine anthelminthics have also been cited as effective against these worms.

Terry Fairfield in "A Commonsense Guide to Fish Health" recommends fenbendazole (Panacur).

Dieter Undergasser in Discus Health recommends a Flubenol 5% treatment.

Garlic added to fish food may help to control this worm.

Mebendazole is used extensively to treat roundworm infections in humans.