OK so take out the goldfish??? Well I have bad news, today a blue gourami and a red one died, so its not looking good at all! I am taking my water in for a test ASAP and I will try and see what's wrong with the tank. It may be that I am over feeding. For the fish I have a feed one cube and 2 servings of flakes a day. Usually a small amount of flakes. I will get back soon.