If the fish is an adult koi, it's a relatively small one, Cohen said. Koi can grow to be up to three feet, according to the Smithsonian's National Zoo and Conservation Biology Institute.

I catch wild koi, goldfish, and swordtails that someone dumped in an urban canal in Miami, Florida! All the fish we netted we brought back to put into our own ponds and tanks!

Koi and goldfish also have the potential to carry diseases such as koi herpesvirus that can harm local fish populations. Motz said animal dumping has been an ongoing issue at Lititz Springs Park.

Motel guest poisons 20-year-old koi fish after fight with management, RI officials say By Paloma Chavez. May 23, 2023 5:12 PM.

A man was arrested after being accused of poisoning 50 koi and goldfish on a motel’s property, Rhode Island officials told news outlets. He is accused of pouring Miracle-Gro in the Stone House ...

A Rhode Island man has been charged with putting liquid Miracle-Gro into a koi and goldfish pond, killing more than 50 fish, officials said. Jeffrey Gronski, 59, was accused of poisoning the fish ...