Mantis are super friendly, the spearing mantis is alot more shy and tend to stay hidden most of the time.
Hammer mantis the peacocks are the best looking for colors, they are super friendly.
I would not keep anything with them they will take an opportunity and eat others, as well your fish that was in the tank would never relax due to the predator that lives there with him.
Adult "hammer" mantis can crack glass (yes its happened to me) younger one's usually are not strong enough.
Care is pretty easy they don't demand to much only some caves (depending on which type) and they love to eat crab.