i wouldnt keep it after a while it becomes high maintanace and you get sick of keeping track of it and where it lives, you cant get small fish or burrowing fish either which becoes annoying.as the mantis gets bigger it looks at different food sources.
beautiful though, i had a g. smithi mantis i loved him he was an awesome pet kinda looks like your pic google it and maybe they are they same.if they are it will stay small
