The scary thing about this monster goldfish found in Lake Tahoe is that the species very likely could disrupt the natural ecosystem in the lake. environmental scientist Sudeep Chandra of the University of Nevada, Reno said,
"During these surveys, we've found a nice corner where there's about 15 other goldfish. It's an indication that they were schooling and spawning."
So this no longer a simple case of somebody dumping out their pet goldfish and everything going on an usual. At this point, the goldfish are producing other goldfish, and they could completely disrupt the lake.
People may not realize it, but dumping your aquarium fish is a big problem both in the U.S. and around the world. It results in anomalies like this monster goldfish found in Lake Tahoe, and other large problems like invasive seaweed and algae blooms.
If you do have unwanted fish, experts suggest euthanasia, calling the pet shop you bought the fish from, or contacting a local wildlife authority. The big lesson here is to not simply dump your aquarium or even flush a live fish down the toilet.