Though flushing “Goldie” down the toilet or setting it free in a creek may seem an expedient option for an unwanted aquarium pet, it just means they’ll end up in streams and lakes, where they can turn into an ecological pest, according to The Ohio State University.
Goldfish are a non-native and invasive fish species in Ohio, according to the college — meaning they’re not supposed to be here, and they can take food away from other native fish, the university’s College of Food, Agricultural and Environmental Sciences reported in 2017.
They’re actually from Asia.
“These invasive goldfish can grow to massive sizes by taking food resources from native species of fish,” the college reported. “They have also been found to eat the eggs of other native fish species even further so hurting their future populations. Goldfish also occupy habitats that native fish use for reproduction as well as shelter and are even able to reproduce with the common carp to produce larger, hybrid species that are equally as detrimental to native populations.”
Improper disposal of dead goldfish can also introduce parasites and other diseases to native fish, according to the college.
The college, citing NPR fish biologist Ben Swigle, recommends freezing dead goldfish overnight before disposing of them in the trash. For live fish, you might consider taking them back to the pet store, or giving them to a new home (in an aquarium, that is).