Hi, I joined up specifically to ask this questions and I'm hoping that someone with experience can help. We have a small fish tank suitable for 6 fish and unfortunately, over the course of a year and a half, they have died. I have noticed that although we leave them the food that Pets At Home recommend to give them while we are away, the slow releasing kind, when we return they have faecal matter hanging from them and over the floor of the tank, and despite a clear up, they pass away from what looks like infection literally within a day of each other, despite leaving the amount recommended by the packet. The tank is otherwise filtered correctly, the water regularly changed, and the fish not overfed while I am at home. But when we go away they seem to die and I am genuinely worried about what is causing it as it has happened a few times now. Please advise. Thank you.