I have one female electric blue crayfish, nearly full size, ready for a new home. it's very healthy, and a deep blue with blackish striations. These craws are freshwater, guaranteed pest and illness free, and each come from a personal 20 g tank. They are slow opportunistic predators and will eat or kill just about anything they can get their claws on, I've had some success keeping them with other fish, over long terms the violent nature of them tends to die down and they accept veteran tank mates that survive. Diet: pretty much anything, these guys get bottom feeder pellets, frozen deshelled shrimp, bloodworms, and sometimes I will buy them 10 or so feeder guppies to enrich them a bit. None of this is necessary, as craws are VERY low maintenance and tend to let you know very clearly when they are hungry. The most important thing is to give them a viable Substrate for digging and making their own caves.