ROCKFORD, Ill. (WTVO) — A popular misconception believes that toilet drains eventually lead to the ocean, but experts say you should never flush a goldfish down the toilet.

There is no U.S. law that makes the practice illegal, but it is still unwise, as fish (dead or alive) can transmit diseases into the ecosystem.

Goldfish are not considered a flushable item, and septic systems are only meant to handle waste and toilet paper.

They also reproduce quickly and do not have a natural predator, and thrive in open waters, and are considered an invasive species, as they can destroy the habitat of native fish.

In 2019, a 14-inch goldfish was caught in the Niagra River, just downstream from the wastewater treatment plant.

The U.S. Fish & Wildlife Service estimates that invasive species have caused $120 billion in damages.

Fish can also carry parasites, which could be the reason a goldfish is dead. By dumping the goldfish down the toilet, you may be introducing that parasite to your toilet or the wastewater system.