The walking catfish is a major invasive species in the U.S. state of Florida.

The walking catfish is native to Asia, common in ponds and freshwater fish farms from Pakistan to the Philippines. The fish's ability to survive in stagnant water makes it a valuable source of food, especially in Southeast Asia.

In the 1960s, aquaculture farmers in Florida imported the fish. Within 10 years, the fish spread to 20 counties in the state.

The walking catfish was able to spread so quickly because of two unusual adaptations: It can breathe air, allowing it to survive out of water, and it can use its spiny front fins to waddle from wetland to wetland.

Mostly, walking catfish navigate the wetlands and canals of southern Florida. They have also been recorded as far west as California and as far north as Massachusetts.

Walking catfish put few native species at risk, as an array of wading birds, such as herons and egrets, are natural predators. However, they often feed in aquaculture ponds, "walking" from fish farm to fish farm, preying on the fish there and causing millions of dollars in damage.

Noun

a modification of an organism or its parts that makes it more fit for existence. An adaptation is passed from generation to generation.

aquaculture
Noun

the art and science of cultivating marine or freshwater life for food and industry.

array
Noun

large group.

canal
Noun

artificial waterway.

fish farming
Noun

art and science of raising and harvesting fish and other seafood, such as shrimp or crabs.

Noun

material, usually of plant or animal origin, that living organisms use to obtain nutrients.

freshwater
Noun

water that is not salty.

import
Verb

to bring in a good or service from another area for trade.

Noun

type of plant or animal that is not indigenous to a particular area and causes economic or environmental harm.

native species
Noun

species that occur naturally in an area or habitat. Also called indigenous species.

navigate
Verb

to plan and direct the course of a journey.

predator
Noun

animal that hunts other animals for food.

prey
Noun

animal that is hunted and eaten by other animals.

wading bird
Noun

bird with long, thin legs adapted for walking and feeding in shallow water.

Noun

area of land covered by shallow water or saturated by water.