What Kind Of Cage Do Rats Like?

When I first purchased my rat, guy, he was small so I also bought a three story hamster cage. Now that he is 8 months older, and bigger, should I buy him a new and bigger cage to give him more room?

Rats will always make use of all the space you can provide for him. Since you have a suspicion that his current cage may be too small, then that probably suggests it is. Hamster cages are not ideal because the levels are simply not tall or spacious enough. The best cage is a really big aquarium with a ventilated mesh roof. You should also try and let your rat out of his cage whenever you can to let him exercise fully.