The idea of a fish walking on land probably sounds like something straight out of a campy low budget horror flick, but believe it or not, the walking catfish (Clarias batrachus) can do just this. Native to Southeast Asia, this catfish has since become well established throughout the swamps and ponds of Florida. It is thought by many experts that these were imported into the country back in the 1960's through the pet trade, and either escaped or were released into the wild. The fish gets its name from its ability to move across dry land for short periods of time when searching for new bodies of water to live in. Walking catfish are able to breath air, and use their wide pectoral fins to pull themselves across the ground, which gives them the illusion of walking.
These fish prefer stagnant waters with high amounts of vegetation and consume a wide variety of food items, including insects, small fish, and algae. In addition to being omnivorous (eating both plants and other animals), walking catfish are extremely opportunistic when it comes to food, and will eat both living and dead prey. These fish are especially problematic for fish farmers, as the fish have been known to make their way into outdoor fish farms and stocked lakes and eat the eggs and/or young of those fish. Like many species of catfish, walking catfish possess sharp spines on their bodies, that secrete venom, so caution should be taken when handling them.
In spite of these hazards that they pose, the walking catfish is relatively low on the destruction list compared to other invasive species in the U.S. This is partially due to the fact that their population hasn't grown a whole lot in recent years, and is not expected to do so either. Populations of these catfish tend to be rather localized throughout other parts of the states, with Florida (of course) being the exception to this. Even so, this species is found mainly throughout the south and central portions of the state, with numbers becoming more scarce as we near the panhandle.
(http://inspectinginvaders.blogspot.sg/2014/01/the-walking-catfish-running-large-risks.html)
Sources:
https://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=486
https://www.floridamuseum.ufl.edu/fish/discover/species-profiles/clarias-batrachus