If they are males i would seperate them unless you have had them both fixed. Two male bunnies will only live together as a pair till about 12 weeks of age then will start to fight. If they are females then just keep an eye on then, they should be ok as long as they were purchased at the same time and same place. Some bunnies will adapt to another bunny living with them if purchased seperate but it is still best to keep an eye on them and see how they go. Good luck.