Smithsonian.com

A giant goldfish recovered from Lake Tahoe. Photo: Department of Natural Resources and Environmental Science, University of Nevada, Reno

Giant goldfish have moved in on Lake Tahoe and begun gobbling up the native minnows. Some of these goldfish weigh four pounds and measure more than two feet long. They’re the very same type of goldfish you’d buy in the pet store: scientists suspect they once lived in home fish tanks, before being dumped into the lake or its feeder streams.

Their monstrous appetites, though, are a problem. Since 1960, populations of native fish in Lake Tahoe decreased tenfold, and researchers fear this new invader could only make matters worse.

Wildlife managers are not surrendering the lake lightly, however. Thousands of invasive fish, mostly bluegills and largemouth bass, have been removed from the lake. It was during those culling efforts that scientists noticed an upsurge in oversized goldfish.

The team plans to tag a few of the goldfish with tracking devices so they can monitor the animals’ activity and devise better ways of getting rid of them. Perhaps the old-fashioned route—handing them out as birthday party favors—would be a good strategy: goldfish sent home with a horde of six-year-olds always seem to die within a few days.

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