There are a handful of threads on crayfish breeding and crayfish as feeders. The red cray (Procambarus clarkii) is too aggressive for aquarium cultivation. The blue lobster is actually a blue morph of Procambarus alleni. A male and a few females can be maintained in around a 55 gal. However, 'berried' females have to be separated out. Then, the female must be removed once the larvae detach. The dwarf cray (Cambarellus schuffeldttii) can have a dozen adults in a 55gal. A fair percentage of larvae may survive with the adults prodided there's a ton of cover (rock work, plants). But, you'll never have enough of these 1 inch crays to make a dent in your fish food needs.
I raise 2 species of Cherax crays. These are large species that require lots of room. I'm expanding an old operation of 20,000gallons of grow-out tanks to 30,000gallons. And, I'm considered a small hatchery owner.