Well I have one in my tank with two other types of rock crabs, a stone crab, a moon crab, and a small wennerea mantis shrimp. Along with a few fish, and I have no issues. NOw I had to put her in a small critter keeper to keep her safe. Since last night I noticed a her carryinng a clutch of eggs. And she is only a size of a nickle. See what happens maybe I can get them to hatch and have a couple survive. That would be awesome.