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Researchers from the University of Nevada, Reno have discovered what they have dubbed monster goldfish, weighing up to 1.5 feet long and 2.4 pounds. Found in Lake Tahoe, the discovery is not good news. The introduction of a non-native species could upheave the entire ecosystem, which is already under threat from pollution and climate change.

In just one small corner of the lake, the researchers found 15 of these monster goldfish, according to LiveScience. Some were even pregnant. While it is unclear whether the fish were deposited into the lake as adults or as youngsters, even a small intruder can cause a big problem. The huge number of them also indicated that they were schooling and breeding.

The monster goldfish are not as huge of a problem as the lake's non-native bass, who outnumber the goldfish by 100 to 1, reports National Geographic. Regardless, both are invasive species, are new arrivals and can lead the way to radically different ecosystems. Goldfish, for example, are omnivores and release a great deal of minerals into their environment. Those minerals can provide what algae need to grow. Lake Tahoe is perfectly clear; the addition of these plants would make the waters murky. One particularly harmful invader, a type of seaweed known as Caulerpa, produces a toxic compound that kills off fish. It is difficult and costly to remove.

The discovery of the goldfish also leads to the question of how they arrived. Goldfish are often used as live bait by fishermen but, according to KCAL, policies are already in place to outlaw that practice. Scientists believe that the monster goldfish likely entered the ecosystem by way of aquarium dumping. It's unknown how many people actually dump their aquariums, but scientists are certain that the practice occurs because the fish would not have entered the ecosystem otherwise. One study in Texas found that between 20 and 69 percent of fish owners admitted to aquarium dumping.

Experts advise aquarium owners not to participate in this practice. If the fish becomes too large or too aggressive to properly care for, they suggest that you call the shop that sold it to you, or your state's department of aquatic and wildlife. They do not suggest flushing your fish down the toilet, because that can cause problems for both the fish and your plumbing.