I had most of my feeder rats in a 10 gallon aquarium. For the number of rats I needed, it was way too small. At PetCo, I found a wire cage addition for a 10 gallon aquarium. It effectively triples the floorspace of the aquarium. I have been wanting to get rid of the aquarium anyways, so I cut a hole in the lid of a 41 qt sterilite tub, and secured the cage on top. Voila! A custom rat cage, with lots of floor space, and in a lightweight configuration that is easy to clean!



The cage addition was $40. The only problem with using it on the aquarium was that the rats urinate & defecate around the edges of the cage, and it falls outside the aquarium. With the sterilite, it just falls on the lid, and is easy to clean off.

I suppose an old birdcage could be used in much the same way. Just leave the bottom off, and secure it to a rubbermaid or sterilite lid.