Corydoras catfishes are very popular in the freshwater aquarium hobby. There are dozens of species within the genus Corydoras and this is by far the largest genus in the family Callichthyidae. These catfishes are native to South America and are exported in very high numbers throughout the year.

In December of 1991 6000 Corydoras schwartzii catfish were imported from Manaus, Brazil by a tropical fish holding facility in Florida. The fish arrived in fair condition (relatively low mortality) and were placed on a recirculating freshwater vat holding system. Several moribund individuals were necropsied and it was noted that these fish contained numerous encysted digenean metacercaria within their musculature and abdominal cavity. Working under the hypothesis that such a parasite load combined with the stresses of shipping and crowding might compromise the health of these catfish a controlled study utilizing praziquantel was established in an attempt to rid the fish of these metacercaria.

The presentation will describe the results of the praziquantel treatment study and will review gross and histopathological findings.