As the mo'creatures mod adds so many mobs you may be tempted to keep them in you're house the suggested mobs for this are the standard tameable mobs but it is possible to safely keep neutral and even hostile mobs In you're house and gardens with use of some handy items and blocks.
Tameable
Cats: A separate room for them is recommended as they require a lot of blocks and items are required to keep them happy. Make sure they have a kitty bed, a litter box, a pet bowl and lots of space.
Big Cats: Best kept similar to vanilla dogs with the use of a big cat whip. They are happy to live in your house or outside with shelter. Be sure to keep your big kitty healthy by feeding it regularly.
Elephants and Mammoths: Best kept outside as the huge mobs might get stuck in walls and roofs indoors. Other than space, these mobs need little attention. However, make sure your beloved pet can't get out.
Ostriches: Are very easily kept in a medium sized pen and look great with a helmet and chest equipped. However, don't attempt to keep wild ostriches, as they can be aggressive.
Lil' fishies: Are simply kept in water with sharks, dolphins and any other water mob. Looks great in decorative ponds and streams.
Snakes: Keep in a pen as even when tame will roam freely. Don't keep poisonous snakes as they bite.
Neutral/Passive
Foxes keep similarly to deer but don't punch it or have a rabbit on you're head.
Deer Easily kept in fenced gardens and pens once trapped although getting them in can be difficult so it is recommended you use a rope.
Rats Keep in a small roofed pen don't enter at night and keep well lit.
Wolves (mo' creatures) Keep in a pen don't enter at night keep well lit and be careful not to attack it
Scorpions Keep in a pen or fenced cave keep well lit and don't enter at night
Birds Keep in a walled roofed pen as they fly and be careful not to let them out
Hostile (not recommended)
Hell rat Keep in a iron cage do not ever enter the cage or realease it as it will attack the player on sight.
Werewolves Keep in a room with an iron door only players can open as at night it transforms in to a humanoid wolf and becomes hostile.
Wraith Keep in a roofed walled pen with a glass window for display and do not enter as they are hostile.
Fire wraith Keep similarly to the normal wraith except it can not be kept in wooden pens or any burnable blocks.
Jelly fish (passive) Keep in the same way as sharks but without the exit be careful as it may sting you
Recommended for creative and advanced players only
All boss mobs Keep in blast proof roofed pens and do not enter EVER!!!
Ogres Keep in obsidian cages and do not enter without sufficient armour and weapons.