An angler fishing in Lake Michigan caught a red-tailed catfish (Phractocephalus hemioliopterus), a popular fish in the aquarium trade that is native to the Amazon. Mike Durfee was fishing at the Portage Lakefront Park when he caught the fish. Eric Fischer, aquatic invasive species coordinator at Indiana’s Department of Natural Resources Division of Fish and Wildlife speculated that the fish was probably purchased when it was two to four inches long and was later released when it outgrew its aquarium.
“The first response of some owners may be to release unwanted fish into the closest natural water body thinking they are helping their pets out by setting them free,” Fischer told the Chesterton Tribune. But doing so can cause a disruption to that environment in that the fish can breed, harbor diseases that native fish have no defenses to and can wreak havoc to their new ecosystem, like that of the invasive lionfish on the Atlantic coast of the United States. “Some aquarium fish, exotic snails, and aquarium plants can permanently disrupt the natural environment,” Fischer said. “Exotic species impact our native wildlife by increasing competition for aquatic resources and introducing diseases.”
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The redtail catfish, though popular in the aquarium fish trade, is not a good fish to keep because they are extremely aggressive and can get very large, exceeding five feet in length and more than 100 pounds in the wild. The fish is popularly known as a tank buster, along with the pacu and the iridescent shark. Although in the aquarium fish trade, these fish are best left in the wild.
Invasive species are a serious threat to the waters in which they are released, and aquarium fishkeepers need to know the consequences of fish species that are released in areas in which they are not native. Lionfish, native to the Ind-Pacific, Hawaii, and the northernmost region of Japan are wreaking havoc on the coral reefs of Florida and the Atlantic seaboard. Snakehead, a popular food fish from China has invaded various lakes throughout the United States, and the Malaysian trumpet snail is established in Florida, Texas, and California. Do not release your aquarium fish. Take them back to the store you purchased them from or if there is no other means to donate or otherwise get rid of them, freeze them and dispose of the body in the trash.