red rash on yellow tangs

[rzelred]

Can someone help me? I have managed to maintain a saltwater tank for the last eight years but I consider myself an amateur. I have three yellow tangs. The oldest and biggest tang has had red spots on the rear half of his body for 3 weeks. Now one of the smaller tangs is also getting this. I do a 35% water change monthly and did one a few days a go.
The rest of my fish are; 1 blue tang, 5 spotted puffers, 1 hawk fish, 2 tomato clowns and 2 percula clowns.
130 gallon tank with CC,
wet dry filter
fluval 403 filter
berlin protein skimmer sits in wet dry filter sump.

 

[hairtrigger]

It could be nitrate or ammonia burn if he was shipped recently. Most likely though it is a secondary bacterial infection. Those aren't usually too complicated to cure. And tangs are hardy fish.
Go to your LFS, they should have antibiotics you can use. I would go with Spectrogram. Or another similar full spectrum antibiotic. That way you can knock out any other secondary infections as well.
Try and get a picture of the problem, or flip through a book on diseass. That might help you diagnose it more. My diagnosis is just an opinion, I can't tell you for sure without seeing it. Sounds straight though. Good luck.

 

[beth]

What are your water readings? Do you have a hospital tank? Are the tangs still acting normally and eating? Have you added any fish resently?