The tank is 40 gallons I think. And, I clean every day anyway, so, that part wouldn't be a problem. I'm looking at just building a wire cage anyway. I just thought that more room and the ability to make levels in the tank to give her more climbing room would be good. But, I wasn't aware that they would experience respiratory problems. I'm going to call my vet, too. there's a lady that works there that rescues rats and she is very knowledgeable. Just getting lots of opinions.