Keeping a Praying Mantis as a pet is easy to do once you learn a few things about them. The first thing you will want to find is a home for your little pet. You can keep them in a nice big vivarium, but Mantises are perfectly content in smaller enclosures with a height of approx. 2.5 times their length and about 2 times their length in width. (So a 2 inch mantis would do well in a container 5 inches tall and 4 inches across.) Whatever you keep them in, they will spend most of their time hanging upside down, waiting on their prey to get close enough for them to grab them with their raptors. Your Mantis will need air, so you will need to make sure that it is ventilated, but you don't want the holes too large, or your pets’ food might escape.
If you decide on a larger enclosure, you will need lots of things for your pet mantis to climb around on. You can use just about anything such as ivy, sticks, etc... Let your creativity guide you. Make sure that all of the items in your mantis enclosure are secured, so that they won't fall on and injure your pet.
Your pet mantis will not need a water dish, as mantises drink water droplets from plant leaves, or from the side of the enclosure. You will water them once a day by misting the inside of their enclosure with a spray bottle. It usually only takes 1 or 2 squirts. Then you can feed them by placing a fly, cricket or other bug in the enclosure with them. They should be fed every day, but they won't always eat, especially when getting close to molting.
If you notice that your pet mantis is not eating for a couple of days, then he or she is likely to molt soon. It is very important that they are not moved or disturbed at this time, as they could fall and it is almost always fatal. So before you touch their container for feeding, or misting them, always look inside and check on them. When they shed their old exoskeleton they are very soft and easily damaged. A few hours after they molt, their new exoskeleton will start to harden and once you see them moving around, it is safe to hold them again.
It really is that easy. I hope you enjoy them as much as I do. If you are wondering where to get a praying mantis, there are a couple of options. You could catch a wild one, although sometimes they are quick and hard to catch. You could check your local pet store and ask if they carry them. Or you can get them online at a place like MantisPets.com