About 4 months ago I decieded to set up a 5 gal tank to keep my feeder shrimp in for my salt water tanks. I have about 4 doz in it at all times. I have a whisper 40 power filter on it for filltration on it. I feed the shrimp live algae which I get from the spring fed pond behind my house. Any way I decided to put some gravel in it from a creek near by, while I was getting the gravel I spied a small crawfish about 11/2 in long. so I caught him and took him home and put him in the shrimp tank with the gravel. It was well worth it. He was a light brown color, now he has growen to over 5 inches and his color has changed from just light brown to two dark bands around his body and bright orange spots on his pinchers and 3 orange stripes on each side of his tail. I put a 8inch conch shell in the tank for him to hide in. He is amazing to watch,he don't ever stop moving gravel around.one day he will have gravel piled to one side of the tank and then 2 day later he will have his shell buied. I have really become attached to him,he does not bother the shrimp in the tank which is ammazing to me,I thaught for sure they would be meals for him, so I feed him shrimp pellets every day and a piece of clam once a week. I had no idea a simple crawfish would be so instering. I wish my reef lobsters would be so instering. So I would advise anyone who can catch one to put one in one of your tanks. Well worth it.