Ever hear those stories about giant crocodiles living in the sewers of New York City??
The myth says that people get them as exotic pets, but when they start to get too big, they flush them down the toilet.
That's all just a myth, as far as we know, but it's the same principal that's leading to giant goldfish in lake Tahoe!!
Apparently people must be dumping their goldfish into the lake when they don't want them anymore.
Because of all the open space and a steady supply of food, the goldfish are growing to monstrous proportions.
Some of them have almost reached 1.5 feet long!!
They are thriving and breeding rapidly, and experts worry that it may drastically change the ecosystem of the lake.
Check out the video (above) to hear how they could seriously affect the lake!