Reports of large, exotic fish that recreational and commercial anglers and fishery-resource managers have caught in public waters nationwide have become too common in recent years. 

The cause for most of these unexpected and environmentally troubling landings is aquarium owners and water gardeners who can no longer care for ornamental fish that have grown to an unmanageable size. These pet owners release the fish into nearby surface waters as a quick solution but may unwittingly cause long-term problems. The release of these fish — and the disease pathogens that may infect them — could adversely affect native fish and result in serious consequences for sport and commercial fisheries.   

Faced with this dilemma, fish hobbyists need to be aware of appropriate alternatives to abandoning their aquatic pets in the wild. The U.S. Fish and Wildlife Service’s La Crosse National Fish and Wildlife Conservation Office is offering owners an option. In 2006, NFWCO formed a government-business partnership in western Wisconsin that includes several area pet retailers. Though these retailers do not offer these frequently problematic ornamental fish for sale, they have nonetheless agreed to accept and quarantine large, unwanted pet fish from owners who can no longer care for them.

Because virtually no market exists for these businesses to re-sell such large fish, the La Crosse NFWCO accepts custody of the fish and humanely euthanizes them at no cost. This partnership program helped to prevent the potential release of 10 large, unwanted pet fish into western Wisconsin surface waters in 2007.          

The partnership is already paying off. Last fall, the Marineland Pet Center in Onalaska, Wis., accepted seven large hobby fish from owners who no longer wanted them. On Dec. 4, the La Crosse NFWCO took possession of these native South American species, including four 10- to 11-inch black-fin sharks and three 11- to 12-inch oscars. NFWCO humanely euthanized the fish with Finquel, a U.S. Food and Drug Administration-approved anesthetic for cold-blooded vertebrates and preserved the fish later that day.   

After a taxidermist prepares them, some fish specimens will become part of an informative educational display. La Crosse NFWCO will use this display for its outreach activities to increase public awareness of potentially problematic pet fish and alternatives to releasing these animals in the wild.