PUBLISHED: 12:58 10 October 2013 | UPDATED: 12:58 10 October 2013
Some of the plants and animals that have been introduced to the UK's canals and rivers have caused problems for our ecosystems.
Invasive species can affect native wildlife in a bad way by competing for food, space, sunlight and water. The animals are often much bigger or aggressive, while the plants choke canals with their rapid growth.
Some examples of these animals are; Killer Shrimp, Zebra Mussel, Chinese mitten crab, Himalayan Balsam, Zander, Water Fern and American signal crayfish