I really doubt that crayfish are capable of feeling lonely. I think your best bet is to provide a variety of plant matter, algae, and detritus to keep it occupied with foraging. I don’t think adding additional fish or crayfish will improve it’s quality of life.

Can crayfish live alone?

Crayfish are territorial and can be aggressive, so it is best to only keep one in a 10- to 15-gallon tank. If you want to keep more than one, choose a much larger tank with plenty of room for everyone. Line the bottom of the tank with about 2 inches of fine sand or very small gravel for him to dig in.

Do crayfish recognize owners?

Crayfish have pinchers as lobsters do, so they could injure someone who tries to pick them up and take them out of their habitat. They will even come up to the walls of their habitat to say hi to human companions whom they recognize over time.

Fish That Can Be Kept With Crayfish

With the small crayfish (such as Cambarellus), you can keep neon tetras, mollies, platies, swordtails and small catfish like Ancistrus. They’ll sometimes eat fish and plants (frogs, too), but fish are seldom eaten because crayfish normally are not able to catch healthy animals.