Crayfish are small fresh-water shell fish that look like miniature lobsters.
If you have ever played by the bank of stream or pond, you may have seen a small animal that looked like a miniature lobster living at the bottom of the water near the shore.
What you saw was a fresh water shell like known as a crayfish. It is easy to see that the crayfish, sometimes called crawfish or crawdad, and the saltwater lobster are close relatives.
Both have 10 legs. The front legs end in large pincers. These pincers are used to catch any prey that comes near, as well as for defense. The four other pairs of legs are used for walking.
The crayfish escapes from danger by swimming backward through the water with quick flips of its fan-like tail. Like the lobster, the crayfish hatches from an egg. A hard shell covers its soft body like a suit of armor.
Several times before it is fully grown, the crayfish must shed its outgrown shell and grow a new and larger one. - Dick Rogers