Giant Snakehead Fish - US Invasive Species

Giant Snakehead
Giant Snakehead | Source

Are Snakeheads a Dangerous Invasive Fish?

Are snakehead fish a dangerous invasive species in the USA? Invasive species, whether they are animals, fish or plants, are causing a huge problem around the world. An invasive species can cause huge disruptions to fragile, local ecosystems, as they often have no natural predators in their new habitat, take over territory and food sources required by indigenous animals for survival and sometimes even destroy terrain. The discovery of a new invasive species in an area for the first time is always a cause for concern.

However, sometimes media reactions to such discoveries can throw people into a frenzy and panic by totally overhyping the possible dangers of their presence to the local population and environment. One such invasive species is the snakehead fish in the United States. They have been dubbed ‘Frankenfish’ or ‘fish from hell’ and there are already many urban myths circulating about these introduced fish. It is said that they will voraciously kill and eat everything they come across, that they can survive for up to four days out of the water, that they can travel great distances across dry land to infest new bodies of water, that they have a poisonous bite and that they can be aggressive towards humans and have even killed them.

Northern Snakehead
Northern Snakehead

About Snakehead Fish

So what is the truth about snakehead fish? They are fresh water fish and are indigenous to parts of Asia and Africa. There are twenty eight known different types and they can vary tremendously in size and colour. They are apex ambush predators, and feed on other fish species, crustaceans, small amphibians and occasionally birds and small mammals. They can grow to a great size and there have been records of snakeheads being four feet long and weighing more than fifteen pounds.

They have long cigar-shaped bodies, large mouths with a protruding lower jaw and sharp teeth and long dorsal and anal fins. Snakeheads start off life ranging in colour from pale greys to golden brown, and darken as they mature to dark browns with black spots. Their preferred habitat is freshwater streams, ponds, ditches and swamps. All snakehead fish are air breathers and they have a high tolerance for water with low oxygen levels.

They guard their young and can become very aggressive towards anything that they perceive as a threat to their offspring. They have acquired their name from the enlarged, snake-like scales they have on their heads. Snakeheads sometimes get confused with the native North American bowfin when they are caught by anglers, as they can look fairly similar.

Giant Snakehead
Giant Snakehead | Source

Have Snakehead Fish Established Themselves in the USA?

Snakehead fish are considered to be an important food fish in Asia and are imported live into America for the Asian food markets in Boston and New York City. They are also popular aquarium fish and are valued for their aggressive natures and toughness. It is thought that snakeheads that have been found in US waterways have either been pets that have been released by their owners or have been released from live food markets in the hope that a growing local population will become a good food source.

The most likely reason that aquarium keepers would have released their snakeheads is that they can no longer afford to feed them, as they are voracious feeders and can consume a great number of prey fish a day. In the summer of 2002 northern snakeheads were caught in Crofton Pond in Maryland, a discovery that caused widespread panic, made the national headlines and local anglers were asked to kill any of these invasive fish that they caught. In October 2002 they were added to the list of injurious species by the US Fish and Wildlife Service, which prevented the transporting of snakeheads between states and banned the importation of all twenty eight species into the USA.

It is illegal to possess snakehead fish in thirteen states, but not in Maryland, the District of Columbia or Virginia. It is, however, an offence to release foreign species of fish into Maryland’s waterways. Live snakeheads have been confiscated in many of the States where possession of these fish has been banned, and to exacerbate the problem further, live specimens are readily available to buy on the internet.

Even the centre of New York is not safe from invasion by the northern snakehead. US conservation workers believe that the invasive species they call the 'frankenfish' can now been found in the lakes of Central Park. Signs have been placed around Harlem Meer in the north of the park to warn anglers that if they catch one of these fish not to return it to the water but to hand it over to officials.

Harlem Meer is due to be surveyed by The Department of Environmental Conservation to see if any snakehead fish are in fact living in the lake and, if so, how may there are. There are worries that if the invasive fish are left to breed unchecked they will destroy the ecosystem in the lakes as they are voracious predators that feed on other fish species and amphibians. The threat of the spread of this fish is taken so seriously that in New York state possession, sale and transport of the live fish and also its eggs is totally prohibited.

Finding individual live snakehead specimens in US waterways is worrying, but the biggest concern is whether or not a breeding population has been established. Breeding populations have been discovered in Maryland, Florida and California, and they have seem to have permanently established themselves in the Potomac River since 2004. In Florida, bullseye snakeheads are breeding in an urban network of canals in the southeast of the State. Most worryingly, there have been live specimens of the giant snakehead caught from Maine down to Arkansas. Giant snakeheads are the largest of these predatory fish, and have been known to act aggressively towards humans and even wounded them. A breeding population of giant snakeheads has not yet been found, and hopefully there never will be.

Why Are Snakeheads Such a Threat to US Ecosystems?

They are voracious apex predators that are potentially capable of decimating the local fish populations, and they also have no natural predators in the US. At all stages of their life they compete with the native fish for food. When they are juveniles they consume zooplankton, small crustaceans, insect larvae and the young of other fish. As adults, 90% of their large appetites are satisfied by eating other fish species, with the remaining 10% consisting of crustaceans, frogs, small reptiles and sometimes even birds and small mammals.

They also carry a disease called Epizootic Ulcerative Syndrome, and scientists are desperately working to determine whether or not invasive snakeheads can pass this disease onto indigenous fish. In contained bodies of water, such as ponds, work has been done to eradicate populations of these invasive fish when they are discovered. A chemical called Rotenone has been used to kill the snakeheads, but unfortunately it will also kill any other fish present in the water.

It is accepted, however reluctantly, that once a population has established itself in a network of fresh waterways that it is almost impossible to get rid of them. As a female snakehead can produce up to 100,000 young in a year, very large populations of the fish can establish themselves very quickly, potentially causing permanent damaging changes to American aquatic ecosystems.

Do you think snakehead fish are a threat to US ecosystems?

  • Yes
  • No
  • On the fence
See results without voting

So while snakeheads are perhaps not the ‘devil fish’ portrayed by a hysterical media, as an invasive aquatic species they have the potential to cause great damage to fragile ecosystems in the US and to out-compete and consume as food the local fish. If you keep them in your aquarium you need to be aware that it is both illegal and totally irresponsible to release them into local ponds or rivers when you wish to be rid of them for some reason. Indeed, we all need to become more aware of the dangers of invasive exotic species in our native ecosystems, and ensure that we do not release any foreign fish, animal or plants into our local areas and also that we report any unusual or exotic species that we do see or catch to the appropriate authorities.


Copyright 2010 CMHypno on HubPages

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Comments 24 comments

CMHypno profile image

CMHypno 2 years ago from Other Side of the Sun Author

Thanks for reading the hub and leaving a comment Jackie. It's not the snakehead fishes fault they have been introduced into countries they don't belong in, but they are damaging local habitats so a solution needs to be found


Jackie Lynnley profile image

Jackie Lynnley 2 years ago from The Beautiful South

I am sure many might disagree but to me these would fit in the category of snakes and my thoughts on those are there is no good one like a dead one! They no doubt will lead to much worse things. Thanks for sharing that info. I do not fish anymore but years ago there was some sort of fish (maybe carp) that would eat your fish if you left them on a stringer in the water which of course was maddening; pulling your line up with only bones on it!


CMHypno profile image

CMHypno 4 years ago from Other Side of the Sun Author

I agree Brett, I don't think that people do think ahead when they are buying exotic animals as pets. A snakehead is for life and not just for Christmas as they say! Thanks for reading the hub, and making a great comment


Brett.Tesol profile image

Brett.Tesol 4 years ago from Somewhere in Asia

I guess people just don't think ahead when buying pets, or 'disposing' of them when they become a burden. What a situation, nature will balance out, but it will surely change the situation!

Voted up, interesting and socially shared.


CMHypno profile image

CMHypno 5 years ago from Other Side of the Sun Author

I will have to check out your Bowfin hub Wesman - seems like you have had some great fishing adventures!


Wesman Todd Shaw profile image

Wesman Todd Shaw 5 years ago from Kaufman, Texas

No thank you! I went fishing a lot this past spring, but didn't catch anything like the snakehead. I guess they aren't around my area - close to Dallas, Texas.

What IS around here is the pre historic Bowfin, a species of fish that looks really similar to the snakehead in shape, but not in colour. Like the snakehead, the ancient Bowfin is a fish that puts of one heck of a fight - a five pound fish will seem to be a 15 pound wish for the fight that it puts up. I wrote a hub about the Bowfin, and went into how it's NOT a snakehead in the article.


CMHypno profile image

CMHypno 5 years ago from Other Side of the Sun Author

Sounds like you should get your fishing rod out then Wesman and sort the problem of this invasive species! Thanks for reading about snakehead fish and leaving a great comment.


Wesman Todd Shaw profile image

Wesman Todd Shaw 5 years ago from Kaufman, Texas

Great hub - I'm told that the snakehead isn't bad tasting, and puts up a heck of a fight - so in other words, it's a great sports fish!

I had no idea that they were in California though.


CMHypno profile image

CMHypno 5 years ago from Other Side of the Sun Author

Go do your research Nicky, there is some info in the hub about snakehead offspring, but you will find a lot more detail on the net. Thanks for reading the hub and leaving a comment


Nicky Smart profile image

Nicky Smart 5 years ago from United Kingdom

i am doing a project at school abought the snakehead could you tell me abought how many eggs they lay and how often thankyou


CMHypno profile image

CMHypno 5 years ago from Other Side of the Sun Author

Glad that you found the info on snakeheads useful, hary Buana, and thanks for reading and leaving a comment


hary Buana 5 years ago

Nice Info


CMHypno profile image

CMHypno 5 years ago from Other Side of the Sun Author

Agree with you daddy yanick, nobody should buy a snakehead unless they are sure that they know how to care for them, and unwanted snakeheads should never be put into local lakes and rivers. Thanks for the read and the comment.


daddy yanick 5 years ago

really this fish is very expensive and dangerous to feed but before buying a snakehead ,we have to be concious about the difficulties of keeping such fish as pets


CMHypno profile image

CMHypno 5 years ago from Other Side of the Sun Author

Snakeheads are causing quite a stir as an invasive species in the US - there has already been a horror film called 'Killer Snakeheads' made. Invasive species are a real problem in most countries and eradicating them humanely is very difficult


katiem2 profile image

katiem2 5 years ago from I'm outta here

I do beleive I've seen snakehead fish in aguariums and pet stores. Very interesting report on the invasive species of snakehead fisn in the US.


CMHypno profile image

CMHypno 5 years ago from Other Side of the Sun Author

Hi jeednyarx, yes it is astounding. Snakeheads are potentially a huge problem for local US ecosystems and invasive species are damaging habitats and out-competing native species in most countries of the world. Thanks for reading the hub on snakeheads and leaving a comment.


jeednyarx profile image

jeednyarx 5 years ago

this is astounding


CMHypno profile image

CMHypno 5 years ago from Other Side of the Sun Author

Thanks for reading the hub on snakeheads, theman. Female snakeheads can lay up to 50,000 eggs and Northern snakeheads spawn in June and July in their natural habitat.


theman 5 years ago

i am doing a project at school abought the snakehead could you tell me abought how many eggs they lay and how often thankyou


CMHypno profile image

CMHypno 5 years ago from Other Side of the Sun Author

Thanks for reading about snakehead fish in the US Sidney and leaving a great comment. I think that every country is experiencing problems with invasive species, and Australia have the cane toads, as well as feral pigs, feral camels, cattle, donkeys etc. Unfortunately, once these invasive animals have established themselves it is very hard to eradicate them


SidneyMorgan profile image

SidneyMorgan 5 years ago from Australia

We have our own version of this down under that has been causing quite problem in Australia. The Cane Toad that was initial brought in to eat the beetles that were threatening the sugarcane plantations, has now out of control and is killing allot of the native wild life.

Thanks for the interesting hub.


CMHypno profile image

CMHypno 5 years ago from Other Side of the Sun Author

Thanks Hello,hello for reading the hub on invasive snakehead fish in the US and leaving a great comment.


Hello, hello, profile image

Hello, hello, 5 years ago from London, UK

Thank you for such an informative, comprehensive hub. I thorughly enjoyed reading it.

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