Ok I'm pretty new to this. My tank has been running for 3 months and my parameters are PH-8.2, nitrate-0, ammonia-0, nitrates-10-20ppm. My firefish developed a smal transparent like spot on middle of his body yesterday and today it's flaking off. Anybody know what it is. I should mention I had 2 clowns die unexpectadly a week and a half after I got them under the same water params I mentioned above. Thanks