I've had little luck keeping Crays with other animals. Even Species Specific tanks can be problematic.

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Crystal Red and Black, Red Claw Macros, Red Cherrys, Green Shrimp, Sulawesi Malawa, Blue Pearls, CPO, Dwarf Crays (C. shufeldtii), South America Puffers, Assassin Snails, Ramshorn and Pond Snails, Hawaiian Actinic Shrimp (Halocaridina rubra), Nerites