A threat to the ecology of Lake Tahoe has emerged in the form of what have been described as 'monster goldfish'.
When researchers trawled the lake for invasive fish species, they caught a giant goldfish that measured 45cm/18" in length and weighed 4.2 lb.
And experts say that the non-native fish are thriving and breeding at a rapid rate, leading to concerns that they will damage the ecosystem of the lake.
"We know that we have a giant goldfish, the question now becomes how long has it been there and how many others are there in the lake?" Dr Sudeep Chandra of the University of Nevada, Reno, told KCRA.
Lake Tahoe is well known for the clarity of its water. Researchers are concerned that this could be threatened by algal blooms caused by the waste excreted by non-native fish, along with the stirring up of sediment as the goldfish grub about in the bottom for food.
Goldfish are becoming an increasing problem around the world, usually ending up in lakes and rivers after being released by their owners when the fish gets too big, or they become bored with them.
It's unclear whether the goldfish were released as adults, or as youngsters, which then grew on in the lake.
Lake Tahoe is located along the border between California and Nevada. It's the second deepest lake in the US at 501m/1645' (the deepest is Crater Lake in Oregon at 593m/1945').
You can see a video of the KCRA news report below:
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