Causes

Argulus popularly known as " fish louse" is an ectoparasite belonging to the crustacean group. This parasite belongs to the Branchiura group and is normally introduced by live food or new pond-reared fish. Parasite is prevalent in many outside ponds and will cause severe damage to body if left unchecked.
Most freshwater species are affected, with especial emphasis on the following families. Bowfins, Carp, Drums, Killifish, Perch, Pikes, Sticklebacks, Sturgeons, Sunfishes, & Basses.
Argulus feeds on host tissue by sucking action of its mouth . The parasite can transmit SVC( Spring Viremia of Carp).

Prognosis

Parasites can be eradicted without too much trouble. Care should be taken to see that all parasites have been eliminated after treatment.

May cause heavy mortality in small fish.

Treatment

Prevention

Try to ensure tanks or ponds are free of parasites before introducing fish, by "sterilizing" them according to good Aquacultural practise.

Contributors

Dr. Chacko, Jim
Unity College of Maine
Fish Patholgy Dept.
Me USA