Snakehead (e.g. Channa argus)

FishFreshwaterAir-breather

Overview

Snakeheads (family Channidae) are elongated, predatory freshwater fish of Africa and Asia, named for the flattened, snake-like shape of the head and the large scales on it. With long dorsal and anal fins, a big toothy mouth, and a robust body, they are formidable hunters. The northern snakehead (Channa argus), shown here, is one of the better-known species. Most striking is their ability to breathe air: snakeheads have a special chambered organ that lets them take oxygen from the air and survive where many fish cannot.

That toughness — air-breathing, surviving out of water for a time, and even wriggling short distances over land — makes snakeheads remarkable survivors at home, but serious invaders where they don't belong.

Note: there are many snakehead species; details here use the northern snakehead as a reference. Treat general statements as approximate and verify against authoritative sources.

Habitat & Range

Snakeheads are native to fresh waters of Asia and parts of Africa — ponds, lakes, slow rivers, swamps, ditches, and rice paddies — often in warm, weedy, low-oxygen water that suits their air-breathing. Some species tolerate cooler climates, which is part of why a few have established damaging invasive populations after being introduced elsewhere, such as in North America.

Diet

Snakeheads are voracious carnivores. Young ones eat insects, larvae, and tiny crustaceans, while adults prey heavily on other fish and also take frogs, crayfish, and other small animals. They are aggressive ambush predators, and their broad, unpicky appetite is part of why introduced snakeheads can hit native wildlife so hard.

Behavior

The snakehead's air-breathing organ (a suprabranchial chamber) lets it gulp air at the surface, so it can live in stagnant, oxygen-poor water and survive out of water for a period if kept moist; some can even squirm overland between water bodies. Snakeheads are also notable parents: they build nests and guard their eggs and young fiercely, sometimes herding schools of fry. These traits — hardiness, big appetite, and protective parenting — make them very successful, for better or worse.

Human Interaction & Conservation

Snakeheads have a dual reputation. In much of their native Asia they are important, prized food fish, farmed and eaten widely. Elsewhere, certain species introduced outside their range (the northern snakehead in the United States being the famous example, sensationalised as a “Frankenfish”) have become serious invasive predators that threaten native fish, and their import and release are tightly controlled. They should never be released into the wild. Consult authoritative sources for status.

More photos of the snakehead