[10] Adult rusty crayfish can reach 10 centimeters (4 inches) in length, although they reach maturity at about 4.4 cm (1.7 in),[11] and can range in color from greenish grey, to reddish brown,[12][13][14] They can be easily recognized by two "rusty", reddish colored spots on the sides of their back and their large front claws with black bands around the tips.

[15] Male rusty crayfish have small hook-like features on their first pair of hind legs that they use to hold onto a female while mating.

The crayfish that wins the most fights is placed at the top of the hierarchy with the other members generally ranking in descending order based on size and sex.

[20] Because the rusty crayfish are able to avoid predators fairly well, their population in these new aquatic ecosystems was able to grow extremely quickly and within twenty years the rusty crayfish population had exploded and become an invasive species in the Northern United States and parts of Canada.

[22] Manual harvest for human consumption is an effective control strategy due to the large size of rusty crayfish.