All 28 species of snakehead can tolerate low oxygen conditions in water because they are air breathers from an early age. When prevented from surface access, adult snakeheads will die due to lack of oxygen.
Snakeheads usually breed in the summer, but some species are known to breed throughout the year.
The female northern snakehead is capable of spawning five times a year. Northern snakeheads can live under the ice of northern climates. Northern snakeheads are the most available species of live snakeheads in the fish markets of New York and Boston.
When snakeheads mate, they are usually monogamous for an entire breeding season, and perhaps throughout their lifetimes.
Parent snakeheads guard their young vigorously. One species (C. micropeltes) reportedly attacked, and in some instances killed, humans who approached the mass of young.
Two species of snakehead are mouth brooders. The male holds the fertilized eggs, and later the fry, in his mouth.
Scientists do not know how many species of snakehead are capable of overland migration, but several are known to do so. Migration is probably an instinctual behavior for species which make their homes in areas subject to seasonal wet/dry conditions. These areas include much of southeastern Asia where the majority of snakehead species are found.
Some snakeheads bury themselves in mud during times of drought. During droughts in Thailand, people looking for food will slice through mud until they locate a fish.
The giant snakehead Channamicropeltes, the most predacious of the species, and one which is known to attack humans, has been collected in waters in Maine, Massachusetts and Rhode Island, where the climate is not conducive to establishing reproducing populations. If it were to be released into subtropical waters in Florida or Hawaii, giant snakehead might be able to reproduce successfully.
Based on water temperature alone, all US fresh or brackish waters would allow some member of the snakehead family to establish itself.
Because snakeheads are so predatory, they pose a high risk to endangered species. Of all endangered species in US aquatic habitats, 16 amphibians, 115 fishes, and five of the 21 federally protected crustaceans would most likely be affected by snakehead introductions.
Source: U.S. Fish and Wildlife Service.