Hi Snazy
Fish are a bit lethargic and look a little thinner, I had full test done on amonia levels etc and all were fine, have not added anything new to the tank recently,its a fluval edge tank and we have the filter that comes with it in the tank. It is a 22 litre tank and we currently have one small tetra, one molly and two plattys and an african dwarf frog in the tank. We do regular water changes and the water is very clear. We also only feed small amount every second day and always have done. The tank has 3 media filters supplied with the tank. The fish only seem lethargic and slightly thinner before they die.thankyou for taking the time to respond.