Having an aquarium at home or in the office may help us relax and unwind but researchers have found that the fish we keep as pets may have an adverse effect on natural water ecosystems. Research has shown that the common practice of “flushing down” our aquatic friends when they have finally kicked the bucket actually harms the environment. According to researchers in Oregon, the number of aquarium fish living in the wild is steadily growing in number. It is their theory that these fish work their way through sewer systems and eventually end up in streams, creeks, and other small bodies of water.

“There’s definitely some mixed messages out there in the popular culture that releasing these things out into the wild is a good thing,” says Paul Heimowitz, Aquatic Invasive Species and Research Coordinator for the U.S. Fish and Wildlife Service, Pacific Region. “Freeing” your pet fish may seem the right thing to do but doing so will have a lasting effect on our water ecosystems.

Aquarium fish disrupt the natural cycle of water ecosystems because they are usually hearty eaters and are not too picky about what they eat. This is especially true of certain aquarium fishes like the oriental weatherfish, amur goby, and the seemingly innocuous goldfish. Oregon researchers say that they are finding these types of fishes in the state's water ecosystems with increasing regularity – and that's not a good sign.

“It’s hard to think of that innocent little goldfish as something that could drive another fish to extinction but we need to realize if they’re in the wrong place, they can be a lot scarier than we envisioned when they were in that little fishbowl,” Heimowitz says.

What Oregon fish experts are trying to say is that, in any case, our pet fish do not deserve to be “flushed down”. In the long run, finding alternative ways of saying farewell will be beneficial for both the pet and pet owner.