Going by my research, these are fairly good tankmates for shrimp. There is a chance they will eat the occasional tiny shrimplet, but they shouldn't be a major predator. They are fully freshwater and fully aquatic. They can be somewhat shy and many fish will eat them, especially during/after molting. They tend to be much more active if there are no fish in the tank. My suggestion for a Thai micro crab tank would be a small tank, set up like a shrimp tank. I wouldn't suggest fish or assassin snails with them, but shrimp should be fine. My LFS keeps a very small tank on their counter. It holds nothing but a ball of moss, some rounded gravel, and three micro crabs. The crabs are always out and unafraid, apparently due to the lack of threats.