Snakehead fish are invasive fish species native to Asia that have been introduced to the United States and other countries, often through the live food fish trade Snakeheads are apex predators with a rapacious appetite, creating major disruptions to aquatic ecosystems they invade
There are 29 recognized species of snakehead fish but the northern snakehead has garnered the most notoriety in the U.S. This species poses a significant threat as an invasive predator to native fish, amphibians invertebrates, birds, mammals, and reptiles.
Understanding the varied diet and insatiable hunger of snakehead fish helps explain why they are so problematic for native ecosystems. Here’s a closer look at what snakeheads eat at different life stages.
What Do Baby Snakehead Fish Eat?
- Zooplankton – Tiny floating aquatic animals
- Insect larvae – Immature insects
- Small crustaceans – Such as freshwater shrimp, crayfish
- Other small fish – Fry and fingerlings of native species
Young snakehead fish start out feeding on tiny aquatic organisms like zooplankton, insect larvae, and small crustaceans. This allows them to grow quickly.
As juveniles get bigger, they graduate to feeding on the fry (baby fish) and juvenile stages of native fish species. This puts them in direct competition with young sportsfish and forage fish that other native species depend on.
What Do Adult Snakehead Fish Eat?
- Other fish – Up to 33% of their own body size
- Insects – Such as dragonflies, damselflies, cicadas
- Frogs – Bullfrogs, green frogs, leopard frogs
- Salamanders – Spotted salamanders, red salamanders
- Snakes – Garter snakes, brown snakes
- Small mammals – Mice, voles, moles, shrews
- Birds – Chicks, ducklings, songbird nestlings
- Crustaceans – Crayfish, freshwater shrimp
As northern snakeheads grow larger, their diet expands to include any prey they can capture and swallow. Adults eagerly feed on insects, amphibians like frogs and salamanders, and reptiles including snakes and turtles.
Mammalian prey is also readily consumed, such as mice, voles, shrews, and muskrats. Snakehead fish even prey directly on birds like ducks, coots, and nestling songbirds. Crustaceans and other fish remain part of their staple diet.
Few freshwater predators can match the diverse diet and voracious appetite of adult northern snakehead fish. A snakehead measuring 33 inches long was found to have eaten a 19 inch long carp, demonstrating their ability to consume other fish up to half their own length.
Why Are Snakeheads Such Voracious Predators?
Several characteristics make snakeheads uniquely effective predators compared to native fish
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Big mouth and sharp teeth – Snakeheads have a large mouth lined with sharp teeth, allowing them to seize large prey.
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Powerful jaws – Their strong jaw muscles deliver a firm bite that gives them a vice-like grip on struggling prey.
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Quick strike – Snakeheads can accelerate rapidly to suck in prey with a swift inhaling motion.
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Voracious appetite – High metabolism requires snakeheads to feed frequently. They will attack any potential prey organism.
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Generalist predator – Snakeheads aren’t picky and feed on a huge diversity of prey across multiple levels of the food chain.
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Opportunistic feeding – Snakeheads will eat whatever prey is most readily available and vulnerable.
With an insatiable hunger and exceptional abilities to capture prey, snakehead fish can devastate populations of other fish, frogs, mollusks and disrupt entire freshwater ecosystems. Understanding their role as apex predators helps illustrate the danger they pose.
Impacts on Native Species
As generalist predators, snakeheads feed heavily on the most abundant and easy to catch prey in an ecosystem. This poses a variety of threats:
- Deplete native fish fry and fingerlings
- Compete with native predators for food sources
- Reduce prey needed by commercially valuable sportsfish
- Transmit new parasites and diseases
- Alter food chain dynamics
- Lower biodiversity
For example, bullfrog tadpoles and juveniles make up a major prey item for largemouth bass. By depleting the bullfrogs, snakeheads are depriving bass of a key food source.
This also allows algae and weeds to grow unchecked with fewer tadpoles eating them. The impacts cascade through the ecosystem.
Preventing Further Spread
Preventing snakeheads from spreading to new watersheds is critical to reduce ecological and economic harm. Here are some tips:
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Learn to identify snakeheads using online guides.
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Never transplant or introduce any live fish into a body of water without approval.
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Contain snakeheads by capturing or killing any you encounter and alert authorities. Never release them.
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Be careful not to transfer water or aquatic plants from one lake or stream to another.
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Spread awareness to anglers, boaters, aquarium owners, and water gardeners about the risks.
Snakehead fish pose a serious threat as invasive apex predators. Their diverse diet and voracious feeding can drastically disrupt freshwater ecosystems they invade. Preventing their spread and population growth is crucial to protect native species.
The Bottom Line
Thanks to their insatiable appetites and feeding versatility, invasive snakehead fish are capable of decimating populations of native fish, frogs, reptiles, birds, and small mammals. Understanding how snakeheads can negatively impact native species helps illustrate the importance of preventing their spread.
Channa argus Northern snakehead fish are native to China, Southern Siberia and North Korea and are an invasive species in North America.
Northern snakehead fish are typically brown with dark, irregular blotches. They have long, thin dorsal fins (the fins located on their backs) and sharp teeth. Northern snakeheads look a lot like bowfin, which is a species that lives in North America. But their anal fin (the fin on the underside, near the tail) is longer, and they don’t have a bone plate between their lower jaws. Male and young bowfins have a rounder tail with a dark spot at the base called an “eyespot.”
Snakeheads can take big breaths of air through their mouths to take in oxygen. This is possible because of a special chamber next to their gills. Because of this change, northern snakehead fish can live on land for up to four days, though this has only been seen in juveniles. Northern snakeheads can also go into torpor, a sleep-like state that lets them survive in very cold places and under the ice.
Northern snakeheads can exceed 33 inches (84 centimeters) in length and can weigh up to 19 pounds (8. 6 kilograms).
Northern snakehead fish are native to China, Southern Siberia, and North Korea. They are an invasive species in North America. In 2002, they were discovered in the U. S. in Maryland and North Carolina. They had likely been imported to fish markets, then unlawfully released. Since then, they’ve been found in parts of California, along the East Coast, and in the Mississippi River and Lake Michigan.
They like to live in swamps, shallow ponds, and slow-moving streams with lots of plants and muddy bottoms. They can also be found in canals, reservoirs, lakes and rivers. Northern snakeheads do best in temperatures between 41 and 60 degrees Fahrenheit (5 and 16 degrees Celsius), but they can live in temperatures as low as 32 degrees Fahrenheit (0 degrees Celsius) and as high as 86 degrees Fahrenheit (30 degrees Celsius). They can live in a wide range of water types and depths because they can adapt to different temperatures, oxygen levels, and depths.
Northern snakeheads usually live for 10 years, but some have been seen living up to 15 years.
Northern snakeheads are aggressive, carnivorous fish with dagger-like teeth. Freshly hatched fry feed on zooplankton, and later, small insects and crustaceans. Young fish eat small fish, but adults can eat fish up to 23 percent of their own body length, like loach, bream, and carp. Adults will also eat dragonfly larvae, beetles and frogs.
At the Zoo, northern snakehead fish eat goldfish, earthworms and crayfish.
In their native habitats, northern snakeheads reach sexual maturity when they are 2-3 years old. In places where they have been introduced, they may reach sexual maturity after only one year. Spawning (when fish release their eggs) typically begins at the end of April and continues through August. A single snakehead may spawn up to five times each year, releasing up to 1,500 eggs each time. Their eggs can hatch within three days.
Snakeheads create large floating nests for their eggs. Once the eggs hatch, the young snakehead fish stay together in what is known as a “fry ball. ” Snakeheads are fiercely protective of their young. The parents stay close by and are ready to scare away any predators by breaking up the circle of floating fry. Once the danger has passed, the young snakeheads rejoin the circle. The protection helps more young fish survive, which increases the number of these fish, even in places where they are a problem.
Northern snakehead fish are native to Asia but an invasive species in North America. Nonnative species that have been brought into an area where they hurt the ecosystems and wildlife there are called invasive species. People think of northern snakeheads as destructive predators because they eat smaller fish and may bring parasites to native species. These mean carnivores can also beat out native species for food and space if they don’t have any natural predators. This makes them a threat to the health of local ecosystems.
Snakeheads were likely introduced to North America through unauthorized, intentional releases from aquariums or live food markets. They have been able to do well in the northern United States and southern Canada because they can adapt to a wide range of environments, spawn large groups (up to 1,500 eggs), and take care of their young. To combat the spread of snakeheads in the U. S. Many states don’t let people ship snakeheads across state lines or own them because of the Lacey Act. However, northern snakeheads are often sold illegally in places where they are not allowed to be sold.
Invasive species have increased as commerce and foreign travel have become more globalized. There are around 50,000 nonnative species in the U. S. alone, 4,300 of which are considered invasive. Nonnative species that get into natural ecosystems can cause problems, but people can stop them from spreading.
Snakehead fish can be found in local waterways. Anyone who sees one should report it to their state’s natural resources department. Any snakehead fish that is caught should not be released back into the water. People who catch northern snakeheads are told by the Maryland Department of Natural Resources to kill them right away. Also, Marylanders who fish for fun are asked to report northern snakeheads by sending an email with a picture of their catch to fishingreports. dnr@maryland. gov with as much information as possible, such as the number of snakeheads caught, the length of each fish, and the exact location where they were caught.
- Pick your pets carefully, and learn as much as you can about them before bringing them home. Exotic animals don’t always make great pets. Many require special care and live for a long time. Small mammals and reptiles from the tropics are often traded across international borders, and some of them may end up as illegal pets. Animals that have been kept as pets should never be let out into the wild.
- As a responsible consumer, make sure that the food you buy comes from legal sources. In the continental United States, it is against the law to buy live snakeheads. In some states, it is also against the law to bring dead snakeheads into the country or have them on hand.
- Share the story of this animal with others. Native ecosystems can be protected by making more people aware of and educated about the dangers that invasive species pose.
- Northern snakeheads can live without water because they have sacs above their gills that take in oxygen from the air and store it.
- Snakeheads can also “walk” on land by moving their back fin and head separately to move forward.
- Snakehead fish are dangerous predators because they eat meat and have teeth that look like daggers.
- lcLeast Concern
- ntNear Threatened
- vuVulnerable
- enEndangered
- crCritically Endangered
- ewExtinct in the Wild
- exExtinct
- ddData Deficient
- neNot Evaluated