Truth and myths about the snakehead fish

by Peter Stern

The snakehead fish is one of the most prolific and ferocious fresh water predators on earth. The head resembles a snake’s head and the body is thin, long and muscular with snake-like patterns on either side. The origin of the snakehead is located in parts of Africa and Asia, but the fish is now found in many other places in the world, including in the U.S.

In Asia the snakehead has become a delicacy and health aid and many areas have developed growing farms to cultivate the fish for increasing spawning and profits. For a while snakeheads were sold from Asia via New York City and from there were redirected to other states. Hobbyists were keeping the fish in tanks to grow them and observe them eat other fish. Many people knowingly (to cultivate them) or unknowingly were releasing these violent and aggressive fish in the wild. In 2002 the snakehead began appearing in fresh water lakes, rivers and streams in New York, Florida, Michigan, Texas and other states. At first, fisherman did not identify the unusual fish. Many threw the fish back into the water. National Geographic provided a brief article on the snakehead, as did a few other newspapers in the U.S. People were told that there was a new species of a vicious freshwater predator fish that killed everything in its path and it could hop up out of water and “walk” on land searching for prey or another lake or pond to feed in. Many states have made it illegal to keep, sell or transport snakeheads over state lines. Some of the media referred to the fish as “Frankenfish” and “Fishzilla” and the names stuck. Many people who read the articles or heard the stories believed the fish would walk into their backyards and devour their pets and little children. Most of these stories were myths and newspaper hype.

The truth is that the snakehead is one of the most prolific and ferocious fresh water predators found anywhere on earth. One female may lay over 250,000 eggs in a lifetime. In addition, most of the eggs hatch and survive because the snakehead is extremely territorial and protective of its young. One hatching may provide 2,000 young and most will survive. The snakehead is carnivorous and immediately attacks any moving object that approaches. While the young fish eat in swarms together as the fish grow older they become solitary hunters, attacking immediately and with fierce stabbing accuracy. If not hungry, the snakehead will kill anyway, for the sheer pleasure of killing. There are different types and sizes of snakeheads which may grow on average to 2 feet long, but the largest grow twice that length.

What makes the snakehead a bigger danger is that it is at the top of the freshwater food chain and has no real thread, so between the huge number of hatchlings and the high rate of survival because it has no enemies snakeheads are moving into more of our freshwater areas and devouring the other fish, frogs, crickets and anything else that enters its territory. In fact, the only freshwater predators of the snakehead in the U.S. are crocodiles, alligators and the bull shark which also has been entering fresh water habitats via open ocean gateways. Some states and towns decided to poison certain ponds and lakes to kill off the snakeheads, but the problem do that is it also kills off the other freshwater inhabitants. Experts are rightly concerned about the onslaught of the snakehead and predict a problem regarding the impact of the snakehead on the freshwater environment in the next decade or two.

It is also true that the snakehead can “walk” on land, but not literally. It can use its body and muscular development to flip across land and survive for up to 4 days if the land contains moisture. At times of flooding or lack of food sources in a pond, river or lake, the snakehead may opt to jump onto land to find another freshwater area to hunt for food. The reason for the snakehead’s adaptability to survive in water and on land is that the fish has a chamber in its head that enables the fish to breathe in and expel oxygen. When the fish is underwater, it must surface periodically only for an instant to breathe in oxygen. As for “walking” along and devouring cats, dogs and babies in the backyard, that is a myth, although snakeheads would attack a human in water if the person swam or walked into the fish’s territory. Snakeheads must be monitored and people need to realize where they are found and to stay clear of them. While the proliferation and expansion of snakeheads into our freshwater system is an issue we should be concerned about, there are many myths about the fish that should be recognized as untrue.