Description

Although this 20 mm long parasite is called a “worm“, it belongs to the crustacean family. It tends to be found in ponds, less in aquariums, in this case on imported wild fish or offspring from field facilities. In the juvenile stages, this parasite can survive for about 5 days without a host. Infection with Lernaea crustaceans weakens the host fish and involves a danger of a fungal or bacterial infection. Please therefore observe the animals after the treatment to verify that the wounds are healing properly. The young are free swimming and borrow into the skin, go into the muscles and develop for several months before showing. They release eggs and die. The holes left behind are ugly and may become infected.

Treatment

Although, the removal of the crab with tweezers is often recommended, this is not advisable, as the head of the crab is deeply embedded in the fish and stays in the fish when part of the crab is torn off. This then results in poisoning from foreign protein.

(Aquarium)

Remove any activated carbon from the filter for the duration of use. Switch off any UV-C appliances and CO₂ fertilizing appliances. Please also ensure that skimmers and ozonisers in saltwater are switched off. Change 50 % of the water prior to application of medication. Aerate the aquarium using a diaphragm pump with air stone during the treatment. We recommend cleaning the filter prior to use of medication.

Treatment can best be done with a 10 to 30 minute bath in 10 mg per liter of potassium permanganate. Or treat the whole tank with 2 mg per liter, but this method is messy and dyes the water.

(Pond)

Prior to use of medication, remove any activated carbon from the filter, switch off UV-C appliances, ozone devices, copper and hydrochloric acid dosing devices if present. Feed the fish sparingly during the treatment. Filter during the treatment. We recommend cleaning the filter prior to use of medication.

After treatment

(Aquarium)

After the treatment, please filter the aquarium water for 24 hours using activated carbon to remove the residues of medication. Afterwards the activated carbon should be duly discarded. The addition of a bacterial starter to the aquarium water helps to replace any purifying bacteria which may have been affected. Please check the ammonium/ ammonia and nitrite values during the treatment and daily in the first days after the treatment. With nitrite values of over 0.5 mg/l an immediate water change of 50% should be carried out and a bacterial starter added.

(Pond)

After the treatment, please filter the garden pond for 48 hours using activated carbon to remove the residues of medication. Afterwards the activated carbon should be duly discarded. After that please change 30 % of the water. Never dispose the pond water into open water or let it trickle away. Always discharge it into the sewage system! The addition of a bacterial starter to the pond water helps to replace any purifying bacteria which may have been affected.