Camallanus / Camallanus cotti

Camallanus / Camallanus cotti were originally spread in Asia and Japan. Due to the worldwide trade in aquarium fish, the parasites are now native to all continents.

Definition of the disease / illness including symptoms

Camallanus / Camallanus cotti infest the rectum of fish. The worms bite into the intestinal mucosa. The worm parts hanging out of the fish’s wide open anus look like red threads. The excrement is light and slimy.

The parasite damages the mucous membrane and sucks blood. As soon as no more blood comes out, it bites into the intestinal mucosa elsewhere. The blood supply of the intestinal mucosa is interrupted, parts of the intestine die. If the intestine is bitten through completely, the worms migrate into the body cavities. The fish eat badly and become emaciated. The stomach is distended. The swimming movements are slowed down. Secondary infections with bacteria and severe intestinal damage lead to the death of the fish.

Summary of the main symptoms

  • red threads hang from the anus
  • the anus is wide open
  • Emaciation
  • pale, slimy stool
  • distended stomach


The parasitosis is caused by Camallanus / Camallanus cotti. In the wild, the viviparous worms, which are up to 2 cm long, are transmitted by copepods. An infection of aquarium fish is also possible without an intermediate host. The larvae of Camallanus / Camallanus cotti feed on cells of the intestinal mucosa and fats. The development into a sexually mature worm takes several months. During this time, the parasites migrate through the entire intestinal tract. Adult worms produce larvae which are excreted with the faeces into the water and can infect other fish. The larvae can also be introduced by live food(mosquitoes, worms).


If no treatment is carried out, the fish of the entire aquarium will be infected. The parasitosis is fatal within a few weeks if the intestine is severely damaged.


The drugs used are lethal for mussels, snails or shrimps in the aquarium. If the infected fish are treated in a separate aquarium, only the worms can be fought. The larvae in the original aquarium survive. Before the treatment, the preparation must be adjusted exactly to the infestation level and the composition of the fish species in the aquarium.

1. Levamisol

The anthelmintic can be mixed into the water of the aquarium as bath water. It is also possible to administer the medication to the fish via treated live food. The preparation causes an increased release of acetylcholine. The Camallanus / Camallanus cotti become spastically paralyzed and can no longer attach themselves to the intestinal mucosa. They are excreted through the anus.

2. Nematol

Nematol contains ethacridine lactate and methyl orange. It does not paralyze the parasites, but kills them completely. Side effects may occur with prolonged treatment. Treatment with Nematol should therefore always be carried out in a separate aquarium. The preparation has a broad spectrum of action and can be used against various parasitoses.

3. Concurat

The product is rarely used today to treat an infestation with Camallanus / Camallanus cotti. The sugar it contains promotes the growth of bacteria. The water quality deteriorates.

A higher oxygen content improves the treatment success. After treatment, the water is filtered through activated carbon for 24 hours.

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