Two times a week for smaller containers is good Anna. Obviously they are doing pretty well as I noticed Red had quite a bubble nest going! If you ever do decide to upgrade him a bit, I know those critter keeper plastic 'tank' shaped containers are nice as well as cheap, and there's more room to decorate in there if you like to do that . Many say adding a small hardy live aquarium plant to their homes make them happy as well as the plant helps break down ammonia better. I haven't tried it yet but I may next time I go to the pet store