I've had a tank w/ fish now for over 3 weeks and the ammonia levels are still high, I've been doing 10% water changes about 2-3 times a week. Of course, I do have 5 fish in there. It's a 5 gallon tank. And I think it may be due to the fact that there has been a lot of decayed food on the bottom of the tank until recently. I just did a 50% water change today and the ammonia is still high. Should I just change all of the water out of the tank? I used to do this instead of weekly water changes back 7 years ago. The beneficial bacteria would still be inside the filter, so should I do this, I'm about to lose another fish and it may be due to this (or it could be the pet store I bought it at, considering the fish I bought from a fish store are doing well). By the way, the fish that looks like she is about to die is kind of turning on her side every so often, would this indicate this was due to ammonia? Plus, is there anyway it could have something to do with the filter? It's a Regent filter that came w/ the tank. Please help!