A nine-year-old Cub Scout found a fish with teeth in Figure Four Lake on Wednesday.
"When it came out I started screaming because I'm not really used to fish," Miles Sherman said. "They're all slimy and sticky and that one had teeth."
With human-like teeth, it's often mistaken for a piranha. According to experts, the fish is actually closely related to the Pacu fish, which is indigenous to South America.
"I was asking myself, 'What the heck is that thing and what's it doing in this lake?" said Carson Sholar, Sherman's fellow Cub Scout.
According to experts at the Houston Zoo, people often buy Pacu fish as pets and then toss them in nearby lakes and bayous once they've outgrown their tanks.
"They tend to gobble up pretty much everything in sight," Mike ConCannon of the Houston Zoo said. "They can destroy that habitat and run them out of the environment."
According to the Texas Parks and Wildlife Department, its administrative code does not forbid the possession or sale of Pacu. However, code 66.015 prohibits the introduction of any species of fish into the public waters of the state without a permit.
The department said they discourage the illegal practice of dumping aquarium fish or plants in the wild, which can be harmful to native fauna.
"We pay money to stock Figure Four Lake," Den Leader Mary Smith said. "Also, we don't want to have a species that's not supposed to be in there, eating up the fish that we want to eat."