fish scales are falling off

[claymore66]

I have a sailfin tang and a bicolor angle in my 75 gal reef tank and the scales seem to be falling off. It is not ick, I have never seen anything like it. I had a perc. clown and he has already kicked the bucket from it. He got so bad his tail and fins were starting to fall off. I have a u.v. sterilizer running and several other fish that seem to be fine. I have several corals in the tank and I am running 400 watts of metal halide 1200 k bulb on the tank about 11 inches above the tank. Could there be to much u.v. radiation getting to the fish? Someone please help and give me some input on what this is. Thanks clay.

 

[claymore66]

The parameters are fine, I check everything every 3 days. As far as other tank mates I have a pink and blue spot goby, a blue strip clown, and a royal gramma, 1 scarlet cleaner shrimp, 1 coral banded shrimp, about 30 blue leg hermits. 10 scarlets, 7 mexican turbos. As far as corals. 1 hydrophora, 3 acropora. 1 candy coral. 4 stalks of xenia. 1 hammer,very large, 1 frog spawn. also very large. 1 cabbage, and 1 blue ultra maxima clam. The newest member of the family is the hydrphora, and acropora. I put them in about a month ago. The tank has been up and running for over a year. Thanks for the reply