Foreign Invasion


Red-bellied pacu/Piaractus brachypomus

A recent video posted on showed a group of fishermen on Percy Priest Lake near Nashville with what they believed to be one of the South American fish known for their sharp teeth and aggressive feeding patterns.

Dan Hicks with the Tennessee Wildlife Resources Agency has seen the video and others like it, and he says the fish is most likely a red-bellied pacu, which is a tropical fish sometimes released after being raised in home aquariums.

“They’re not carnivorous,” he says. “They are a tropical fish and they will die in the winter here. We know people buy them in pet stores and they sometimes wind up in our waters here.”


So it seems that the area lakes and streams are safe from piranha, but that doesn’t mean that the TWRA isn’t concerned with invasive species and the damage they can do to local ecosystems and native fish.

“We look at populations of several species of fish in the reservoirs and if we see a problem in over- foraging or habitat loss we try to take action,” says Mike Jolley, TWRA reservoir fisheries biologist for Region 3, which includes waterways in the Chattanooga area. “In western Tennessee, we are seeing the Asian [silver] carp which are possibly working this way, but they aren’t really a problem here at this point.”

Tennessee law prohibits the possession of 11 species that are considered dangerous to aquatic ecosystems in the state. These include fish such as round goby and bighead and black carp, and other water-based wildlife like the New Zealand mud snail and zebra mussels.


Zebra mussel/Dreissena polymorpha

“The zebra mussel is really at the forefront now in the systems I work with,” Jolley says. “They compete with the smaller fish for the plankton and remove a lot of nutrients from the water.”

To help boaters and fishermen reduce the risk of introducing non-native species into local waters, the TWRA has a website that offers tips to help prevent the transfer of wildlife from one area to another. “The biggest thing we’re doing right now is prevention and education for boaters that are moving from one body of water to another,” Jolley says. “Cleaning out your bilges and not transferring water between systems is really important.”



Late fall can be a good time to switch to fishing for smallmouth bass in Tennessee. All bass will be feeding actively to prepare for the winter. Using minnows or lures that look like minnows in shallow water near submerged cover is a good strategy for all bass, especially smallmouth as the temperature drops.

To learn more about invasive species threatening Tennessee’s lakes and rivers and tips to protect our waters, visit:


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