Crayfish are small freshwater shellfish with five pair of legs; they resemble a little lobster, are related to the lobster and are quite delicious. The prawn is more like a shrimp, although it is more significant in size, is considered marine life, so it does not live in fresh water. Crayfish have claws, and their meat is less sweet than that of prawns. Also, you do not get as much meat from the crayfish. Prawns are closely related to shrimp.
Crayfish are also known as crawfish and crawdads. Prawns have more protein than the crayfish, probably because they are larger and hold more meat. The prawn is more natural to peel and eat, and the crawfish has a shell that is hard and difficult to crack open. All in all, the prawn is more desirable because of its flavor, ease of peeling, and just more comfortable to eat.