I know my goldfish are in a 20gallon and i'll need to move them. But i went to petco and purchased a new filter, a penguin power filter 200. And the difference in water quality in half an hour is amazing. And the fish seem a lot happier. I'm fasting them until monday morning since they all seem so bloated. And i purchased a siphon gravel cleaner and was very frustrated. When all of a sudden. BOOM. It started working. And man did i suck up a lot of stuff. Two full brown buckets of water. I'm so happy to see my fish happy.