how big is the mantis? that'll help determine tank size, usually they'll need something between 24 & 30g depending on their size, but of course the bigger the tank the better. they'll eat anything in terms of diet, i feed mine frozen krill and then something hard shelled at least twice a weak (snails, hermits), they like silversides too. i have a 4in peacock in a 24g nano cube, i keep corals with him too. corals are fine with the mantis and the type you can keep depends on your lighting, however, mantis don't like very high lighting, pc's are good. for my nano i only have carbon basically, i can't fit a skimmer, but i'm sure a skimmer would be better since they're messy eaters. i definitely reccomend a peacock, they're beautiful and fun to watch. i hope that answers everthing
