January 30, 2001

1 min read

Google Logo Add Us On GoogleAdd SciAm

Don't Free Little Willy

By Kate Wong

Join Our Community of Science Lovers!

Image: Courtesy of the U.S.G.S.

You thought that an aquarium and its exotic inhabitants would bring you hours of delight and relaxation. Instead maintaining it seems like a full-time job. Flush the fish? Too cruel. Probably better to release them in the nearest body of water and let them swim free, right? Wrong. According to the U.S. Geological Survey, dumping those creatures is about the worst thing you can do, both for them and for the ecosystem.

In a non-native habitat, fish become susceptible to parasites, diseases and predators that they are not equipped to fend off. At the same time, they may prey on or compete with the native fish, or even infect them with their parasites and diseases. Former pets can thus quickly become formidable pests. (Some aquarium species¿freshwater stingrays and piranhas, for example¿can also pose a serious public health threat.)

On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.

People looking to get rid of their aquarium fishes, says U.S.G.S. biologist Pam Fuller, should consider returning them to the local pet shop, giving them to another hobbyist or donating them to a public aquarium, school or hospital.

Kate Wong is an award-winning science writer and senior editor for features at Scientific American, where she has focused on evolution, ecology, anthropology, archaeology, paleontology and animal behavior. She is fascinated by human origins, which she has covered for nearly 30 years. Recently she has become obsessed with birds. Her reporting has taken her to caves in France and Croatia that Neandertals once called home to the shores of Kenya’s Lake Turkana in search of the oldest stone tools in the world, as well as to Madagascar on an expedition to unearth ancient mammals and dinosaurs, the icy waters of Antarctica, where humpback whales feast on krill, and a “Big Day” race around the state of Connecticut to find as many bird species as possible in 24 hours. Wong is co-author, with Donald Johanson, of Lucy’s Legacy: The Quest for Human Origins. She holds a bachelor of science degree in biological anthropology and zoology from the University of Michigan. Follow her on Bluesky @katewong.bsky.social

More by Kate Wong

It’s Time to Stand Up for Science

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.

I’ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.

If you subscribe to Scientific American, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.

In return, you get essential news, captivating podcasts, brilliant infographics, can't-miss newsletters, must-watch videos, challenging games, and the science world's best writing and reporting. You can even gift someone a subscription.

There has never been a more important time for us to stand up and show why science matters. I hope you’ll support us in that mission.

Thank you,

David M. Ewalt, Editor in Chief, Scientific American

Subscribe