Researchers say that the fish — likely the result of people dumping aquariums into the lake — have been resident there for years, reports The Los Angeles Times. The releasing of non-native fish into Lake Tahoe is illegal.
One such fish — caught in 2011 — measured 14 inches long and weighed 4.2 pounds. Reporting at a conference on invasive species, researcher Sudeep Chandra said that once the fish are in the lake, they can multiply quickly. The goldfish then eat the native fish and excrete waste that Chandra says is like Miracle-Gro. This causes algae to increase and chokes the waters of the lake.
Goldfish aren’t the only invasive species in Lake Tahoe. The U.S. Department of Agriculture Forest Service warns that largemouth bass, bluegill and crappie as well as other warm-water species are invading the region’s lakes and rivers.
A website for the Forest Service warns that goldfish are, “Goldfish are among the most destructive non-indigenous species in North America, primarily because of their diet of aquatic vegetation.”