Tang sickness?

[stephanie]

Is there a diseases that just effects tangs? I have had 2 very healthy looking tangs die now and the only symptom that I saw on one of them was a slightly sunken in face and a pink spot on his cheek. A tang from my other tank had a very similar thing right before dying, except he was sick from the minute I got him. In that same tank there was a VERY healthy looking yellow tang that just died. I thought he had gotten caught by my brittle star. I was watching the yellow tang thinking he really was a nice healthy looking fish, then a couple of hours later he went missing. I am really frustrated! I have lost a red sea sailfin tang, Yellow Tang, Kole tang and powder brown tang! Every time I check my water parameters they look good. The major thing that I have done different is I went from changing 10% every 10 days to 20% every 20 days. Possibly this is too much for the tangs. All the other fish in the tank seem fine.

[Hewey McLovit]

I lost one of my Yellow tang about 2 months ago, after doing a larger water change. Up until that time there was no issues and i saw no visible signs b/f the water change. Post the water change the tang became began to show a decreased interest in food, although it was still eating, which resulted in general wasting. I have now started to do smaller, 5-10 gallon water changes, biweekly and the tank is happier. Spoke to a couple of shops and they thought it may have gotten an intestinal parasite. IDK