This 17-inch pacu, weighing almost 3 pounds, could no longer be maintained by its owner and was briefly sheltered at the Marineland Pet Center in Onalaska, WI. The La Crosse NFWCO later took possession of the fish, preventing its possible release into the wild. Photo credit: USFWS.

This pacu was prepared by a taxidermist and is now displayed by the La Crosse NFWCO to highlight alternatives to the release of large, unwanted pet fish into the wild. Photo credit: USFWS.

Reports of large, exotic fish caught by anglers, commercial fishers, and fishery resource managers in public waters have become all too common across the country in recent years.  The causes for most of these unexpected and environmentally troubling landings are hobbyists (aquarium owners and water gardeners) who can no longer care for their ornamental fish (e.g., pacu, koi) that grew to an unmanageable size and were purposely released into nearby surface waters as a quick solution.  Pet owners should know that the release of these fish (and the disease pathogens that may infect them) could adversely impact native fishes with serious consequences for sport and commercial fisheries.  Faced with a dilemma like this, fish hobbyists need to learn of approved alternatives to the illegal abandonment of their aquatic pets in the wild.  One such option, now offered in western Wisconsin, is a government-business partnership that was established in 2006 by the La Crosse National Fish and Wildlife Conservation Office (NFWCO).  Several pet retailers in this region (that do not offer these frequently problematic fish for sale) have agreed to accept and quarantine large, unwanted pet fish from owners who can no longer care for them.  Because there is virtually no market for these businesses to re-sell such large fish to other pet owners, the La Crosse NFWCO will accept custody of these unwanted fish and humanely euthanize them at no cost.

Due to this unique partnership with local businesses, the Marineland Pet Center in Onalaska, Wisconsin, recently accepted four large hobby fish from owners who no longer wanted to care for them.  On August 15, La Crosse NFWCO biologist Mark Steingraeber took possession of these tropical species which included three oscars (10-11 inches total length) and one pacu (17¼ inches total length) weighing 2.8 pounds, the largest pet fish received to date.  These fish were humanely euthanized with Finquel® (tricaine methanesulfonate), a U.S. Food and Drug Administration-approved anesthetic for aquatic cold-blooded vertebrates, and cryopreserved later that day.  With the receipt of these fish, this unusual partnership has helped to prevent the potential release of seventeen large, unwanted pet fish into Coulee Region surface waters during the past two years.  Some of these colorful specimens have been prepared by a taxidermist and are displayed in an aquarium at outreach events to increase awareness of potentially problematic pet fish and acceptable alternatives to the release of these animals in the wild.