This is a good addition to a fish tank to provide more room for your gerbils or hamsters however, my major complaint is that its difficult to access the tank unless you take the entire cage off the top of the tank. I wish there was a door on one of the sides of the cage instead of on top so it would be easier to top up the food dish, add chew toys, or even just access your pets! The ladders are also prone to coming unhinged and falling down. I think its a bit expensive for the inconvenience of having to remove it every time you want to take your pet(s) out, and keep putting the ladders back up, but it has proved to be chew proof against our voraciously gnawing gerbils, so Ill give it that!