SACRAMENTO --  Researchers are concerned about a fish that's turning into a new threat to the ecology of Lake Tahoe.

Biologists with the University of Nevada, Reno say they're finding a growing number of giant goldfish in the lake.

Stories have been around about large goldfish, but no one had been able to document the species until now.

Christine Ngai, of the University of Nevada, Reno, was among the researchers who found the first goldfish during a survey of invasive fish in the lake.

“You just see this bright golden orange thing starting to float up, and you’re like, what is that? And then you take a net and you scoop it up and you’re like, it’s a goldfish,”  Ngai said of the initial discovery.

While officials have been working for years in trying to keep the lake's water crystal clear, researcher Sudeep Chandra said the discovery of the goldfish is particularly worrisome because goldfish eat a lot and excrete "lots of nutrients."

Those nutrients stimulate algae growth.

The goldfish, some of which have grown to 18 inches, could also eat smaller fish, creating new competition for native trout.

Chandra says with no prior studies on goldfish for guidance, researchers are catching the giant goldfish and bringing them back to their lab to study.

It's not clear how the goldfish got into Lake Tahoe, but it's believed to be from people dumping aquariums into the lake.

Although policies currently exist to limit the introduction of invasive species, some believe a new campaign to curb aquarium dumping may be necessary.