America's 9 most dangerous and costly invasive species

Snakehead Fish The first time a snakehead was seen in Maryland was when an angler caught an 18-inch specimen in 2002, 20 miles north of Washington, D.C. Since then, they've been caught in dozens of bodies of water, including the Potomac River and tributaries, leading to the nickname "<a href="http://www.foxnews.com/us/2012/04/05/maryland-puts-gift-card-bounty-on-fish-from-hell/">fish from Hell</a>." (AP)

Canadian Geese Nearly extinct 100 years ago from over-hunting, conservation efforts have seen a huge and devastating rebound in New York's geese population. Over the last ten years, they have struck 78 planes in the area, costing millions and killing at least 24. Indeed, 2009's "Miracle on the Hudson" crash was due to, you guessed it, Canadian geese. (D. Gordon E. Robertson)

Pythons Giant snakes have taken over Florida, devastating the local ecosystem, proving a menace to pets, small children and even alligators (pictured). (Reuters)

Giant African Snail Almost half a century ago, a young boy smuggled three giant snails into Miami. Within years, the number reached nearly 20,000. Florida has since spent millions trying to eradicate the beasts, which can grow up to eight inches in length. (AP)

Red Fire Ants According to the Arizona Sonora Desert Museum, red fire ants were imported to the States around the 1930s and now attack five million people a year, sending 25,000 of those people to the hospital. (AP)

Asian Carp Asian carp recently invaded the Great Lakes, a notoriously fickle freshwater ecosystem. Because of their growth and reproductive rates, Asian carp can quickly dominate and devastate local fish populations. (USGS)

Asian Mongoose The Asian mongoose was introduced to Hawaii to protect sugar cane fields from rat and snake damage. Instead, they took over, preying on birds and reptiles, hurting local industries and ultimately costing Hawaii $50 million in damages a year. (Carla Kishinami)

African Honey Bees These "killer bees" entered the U.S. ecosystem in 1957 when some specially bred bees escaped a science lab. Now swarms can be found all over the southern United States and have been known to inundate and kill animals by stinging them over 500 times. Ouch. (AP)

Zebra Mussels In the U.S. and Canada, they were first detected in the Great Lakes in 1988. They damage harbors and waterways, ships and boats, and water treatment and power plants. (U.S. Army)