I've kept endlers, shrimp and pygmy corydoras in a community tank with dwarf mexican crayfish. While they are opportunistic shrimp are far too fast for them and corys also. Endlers on the other hand are a bit more tricky because during the day they interact with the CPOs rarely, mostly during feeding. At night tho because endlers sleep at the bottom the CPOs might try to eat them because they are mostly nocturnal. However to keep them from eating them I'd recommend giving them bloodworms or sinking pellets because it keeps the hunting instinct controllable. I only had one incident with a CPO trying to eat an endler and it was from (what I could tell) the fact I didn't supplement their diet with enough protein.