River Cancer is one of the largest crustaceans, and can grow up to 18 centimeters long and weigh 350 grams. Crayfish occur in freshwater lakes and flowing waterways. Crayfish moves generally walkin above the bottom. To escape enemies, they can quickly move backward through nature with its powerful tail.
The spread of crayfish is currently very limited because it is so marginalized.
In Sweden, crayfish and red-listed as endangered by the crayfish plague. Crayfish plague is spread mainly through illegal releases of signal crayfish.