Hi Guys

Thanks for the responses. I am using strips. The nitrates and nitrite readings are zero (white). I didn't know there were other testing methods. Is this liquid you mentioned available in most pet stores? I will definately start changing the water more often and switch off the heater. I'll keep you posted on the progress of the two remaining fish. I certainly won't get any more for now. How many should I keep in this tank. The most I had were 4 (2 fantails and 2 small black moors). Now I just have one fantail and one gold comet.