Some Invasive Fish in Florida Can Breathe Air and Even Walk on Land

Home to many unique, colorful, native tropical fish, the Sunshine State has also become the breeding ground for dozens of invasive fish species. Some of them, like the lionfish, look exotic and beautiful, but they’re actually quite harmful to the ecosystem. There have been hundreds of non-native fish introduced to Florida waterways over the years, but not all of them are considered invasive. Learn what invasive species do to the environment, and discover some of the most invasive fish found in Florida’s waters.

What Is An Invasive Fish?

Any fish that has been introduced to areas outside of its native range is considered non-native and may become invasive. Invasive fish are species that are harmful to native plants and animals, human health, and/or the local economy. In some cases, exotic fish released from aquariums by pet owners are the source of invasive fish species. However, some species have been purposefully introduced into waterways, such as those that help fight other invaders or are stocked to enhance fisheries. Other species that have been introduced have found success in the area, such as the butterfly peacock bass (Cichla ocellaris), native to much of South America including Venezuela, Brazil, and surrounding countries. They have not caused significant damage to the environment and are now some of the most popular game fish in the state.

Invasive Fish Species In Florida

There are both marine and freshwater invasive species in the waters of Florida. Despite the large numbers of non-native introductions, fortunately, only a segment of non-native species that are established in these waters actually becomes invasive. Take an in-depth look at some of the most invasive fish species in the state.

Red Lionfish (Pterois volitans)

Perhaps the most well-known invasive species in Florida is the red lionfish. It is a marine species originally from the Indo-Pacific region. These fish have red, brown, and white stripes, with large, feather-like pectoral and tail fins. Lionfish measure around 12-15 inches in length, but some have been recorded to exceed 18 inches. These fish defend against predators with 18 venomous spines that can cause serious injuries when handled.

When properly prepared, lionfish are safe to eat. They are found near coral reefs, where they eat the native fish. This causes ecological problems, as they consume fish that keep the algae population in check on coral reefs. They also compete for resources with native predatory fish.

Blue Tilapia (Oreochromis aureus)

Blue tilapia are native to tropical and subtropical Africa, including northern and western regions, and the Middle East. They are primarily a freshwater fish, found in rivers, streams, ponds, lakes, and even canals. These fish are also tolerant of saltwater and may be found in some estuaries like Tampa Bay.

Blue tilapia are generally blue-gray with pale underbellies. The edges of their dorsal and caudal fins are shaded pink to red. The largest blue tilapia caught in Florida measured over 21 inches in length and weighed 9.57 pounds. These invasive fish aggressively compete with native species for food and spawning areas.

Clown Knifefish (Chitala ornata)

Known as the clown featherback, spotted knifefish, or clown knifefish, the Chitala ornata is a flat, silvery-colored fish with a long anal fin, small dorsal fin, and black spots ringed with white. The largest clown knifefish documented in Florida measured 31 inches and weighed nearly 10 pounds. The fish is native to freshwater habitats in Cambodia, Laos, Vietnam, and Thailand. In Florida, it is currently only found in the southeast, thriving in Lakes Osborne, Ida, and their associated canals.

Clown knifefish are known for hunting practically any fish that fits in their mouths. They also school together, making them a threat to smaller fish. They can breathe air to survive in stagnant water with little oxygen, so they are exceptionally hardy fish in otherwise challenging conditions.

Walking Catfish (Clarias batrachus)

Walking catfish are native to freshwater in Southeast Asia. However, they are able to breathe air, and they “walk” across dry land to find food or a better habitat when the water dries up. These fish wiggle their way across the land using their pectoral fins to keep themselves upright. Walking catfish live in slow-moving and stagnant bodies of water, such as ponds, swamps, streams, flooded fields, or temporary water sources.

Walking catfish have dark grey or greyish-brown, elongated bodies with white spots. The largest individuals in Florida rarely exceed 14 inches in length, but they can grow up to 20 inches. A stinger or thorn-like barb lies hidden in their fins. Painful pricks from their barbs may lead to infection if you are pricked by one of them. These unusual fish are considered invasive because they can live and reproduce even in harsh conditions, and they compete for food with native fish and prey on their eggs.

Snakehead (Channa species)

Snakeheads are air-breathing fish endemic to Pakistan, Malaysia, and southern China. These fish generally have brownish, torpedo-shaped bodies with black blotches. They have flat heads with toothed jaws and long dorsal and anal fins that lack spines. The largest snakehead caught in Florida measured 31.5 inches and weighed 9.2 pounds.

Their range in Florida is centered around the Margate/Coral Springs/Pompano Beach area, and they are likely limited to the southern part of the state, as temperatures below 50°F are fatal. These fish are often found in canals with dense aquatic vegetation. These fish are invasive because they are adaptable, have no natural predators, and will ambush and eat almost anything in the water.