Description and treatment of anchor worms
Anchor worms are so called because it has an organ that looks like a ship’s anchor which it uses to attach itself to the body of a fish. Scientists call anchor worms Lernea. This is a parasite that is visible to the naked eye. What you will see is long straight worm like lines attached all over a fish’s body. The end of the “lines” forks into two parts. These are actually the egg pouches of a female anchor worm. There are male and female anchor worms but the male anchor worms die after mating so you will mostly see the females.
The harm caused by anchor worms
Anchor worms don’t just attach themselves to the body of the fish but actually embed the “anchor” deep into the flesh, muscles and even as deep as internal organs. Where the anchor worm penetrates the skin a swollen red ulcer will develop. This sore usually leads to secondary fungal or bacterial infections. The anchor worm drains the fish by feeding off its blood.
Life cycle of anchor worms
The female anchor worm will release her eggs into the water when they are about to hatch into free swimming larvae. These larvae will swim about for up to a week looking for a fish to attach itself to. If they don’t attach themselves in this time they will die off.
The larvae will go through a juvenile stage and an adult stage. At the adult stage they will mate, with the males dying off, leaving behind the females with her eggs. The females stay attached waiting for her eggs to mature.
Treatment of anchor worms
To treat anchor worms successfully, you need a two pronged approach. One part involves taking each infected fish out of the aquarium, one by one to remove the anchor worms. Use tweezers and grab the anchor worm near to the attachment point. Grab tightly and pull it out quickly before the worm has a chance to react. Dab the sore on the fish with an aquatic antiseptic. The second part of the treatment involves adding a chemical treatment to the water to kill off any free swimming larvae in the water. Use an organophosphorous insecticide such as metriphonate.
After one week repeat the treatment. Remove any new anchor worms that have attached and treat the water again in case there are any new free swimming larvae.
Luckily anchor worms are quite rare and when it does occur they are easily spotted. Infection usually comes from newly introduced fish or from birds that bring it to ponds.