Aquariums are no good for GP's! I would check out the sneezing also watch her/him carefully because when my guinea pig started sneezing he also stopped eating and lost a lot of weight. It ended up that he had gotten sick and I went to the vet and he had the flu and was very close to dieing and I had to give him shots for a week. Thankfully he is much better, but it happened really fast so keep an I on her and it doesn't hurt to take her to the vet for a check up anyway. Also the cages made out of coroplast are really great I just made one and my guinea pig loves his new cages and he has a lot more space also!!! Good Luck!!!