Hey thanks for the reply. My tank is a 29 gallon. There are 4 neons, 2 gold barbs, 1 zebra danio, 1 lepoard danio, 1 blue ram, 2 kribs and 1 flying fox. The catfish i have had for nearly 3 years, he is my oldest fish and was always really hardy. My ammonia, nitrates, nitrites and pH are fine...