In Ira's case I am sure a familiar is appropriate...
There was also a case of coarse fishermen illegally bringing in species (I think they were eggs - but someone may correct me here, and I am sure they will) to release so that they had some more freshwater sport fish to catch.
There are Rudd and European Perch (Perca fluviatilis) here as well, I have caught a perch in a lake, it was rather tasty.