- Organisms that are outside of their native land like the Round Goby are invasive species. Invasive species can wreck havoc in other environments. Invasive species take over our environment and many others. Invasive species hurt our economy in many different ways. Invasive species in Canada: Asian carps, Sea lampreys, Zebra Mussels, Green crabs, Clubbed Tunicate, Japanese oysters, Round Gobies, Rusty crayfish, spiny water fleas are very dangerous. Invasive species normally compete with native species for food and habitat
Loaches are the world's most invasive species (not 100% verified)
Here is a report on one of North America's most dangerous crustacean, the Rusty Crayfish.