your fish have Camallanus, an intestinal parasitic infection caused by a nematode (parasitic worm) which is found in wild fresh and salt water fishes throughout the world.
The disease is characterized by, among other things, the presence of tiny red thread structures protruding from the anus of the infected host fish. Close inspection of the victim shows a swollen and irritated vent area. The worms can actually protrude 1/3 to 1/2 inch from the anus of the infected fish. This is about one fourth to one third of the worm’s length. The worms are red from the victim’s blood in their gut.
As with most parasites, there are two main body functions of this worm, reproduction and nourishment. The attachment inside the fishes gut is by what appears to be a simple row of long hooks. Closer examination reveals a burr-like structure. Attachment to the intestinal wall causes considerable damage to the host’s intestines. The remainder of the body of the worm is dedicated to reproduction.
Microscopic larvae from this parasite are constantly being produced and sloughed into the water. A secondary host is necessary to carry on the life cycle. once established in the copepods found in most of our tanks, the nematode infection is easily transferred from hobbyist’s aquarium to aquarium with nets, feeding utensils, water change devices and simple aspiration of splashes and spray from one tank to another. This carries the infection rapidly around the hobbyists’ fish room in a matter of days.
The early signs of the parasite’s presence are typically unnoticed. The victims show a minor swelling of the belly and may go off their food. Usually the fish have no problems laying eggs until the infection has reached the stage of showing protrusion from the anus. In the end, the anus and reproductive organs of the fish become so irritated and inflamed that secondary infection sets in and the swelling causes enough hemorrhaging to cause the victim to bleed to death or it dies from internal bacterial infection.
In addition to this obvious outside appearance, the worm has been found in the body cavity of infected hosts. This may explain some of the mysterious deaths one sees in fishes which have been successfully treated for the nematode. The adult worm has died inside the body cavity and decayed inside the host fish.
treatment:
purchase a bottle of about 18 grams active ingredient from an online agricultural supply company or farm store for under $20. (shop around).
divide the product into 5 gram packets (standard fishroom measuring spoons will help you here).
mix a 5 gram packet with 3 ounces of water and keep in an opaque bottle to make roughly a 5 percent solution. keep remaining product refridgerated for up to 3 weeks.
dose 1 ml. of 5 percent levamisole solution per 10 gallons for 36 hours. (1ml. is about 1/5 (one fifth) of a teaspoon. be sure to remove carbon from filter during treatment.
do a 45 percent water change following the 36 hour treatment and install new high quality carbon in your filter.
feeding frozen or live brine shrimp after treatment is a good way to facilitate the clean out of any dead worms from the fish's digestive system.
most fish can tolerate 1 ml. per 5 gallons and this is a good dose for newly acquired fish if you're quarantining them. higher doses than this can kill weak or juvenile fish.
fish may appear 'groggy' during the 36 hour treatment but this will dissipate.
