Here's one that stumped us, but we survived!

[jarrod]

We have a Blonde Naso. About 2 months ago we noticed the veins in his tail fin were real bloody looking and his overal body was turning dark, almost black. We couldn't find anything in any book about a fish turning dark (only white, excess slime, or cottony). We ended up treating him with Maracyn-Two since the only thing we could come up with was possibly a bacterial infection. Luckily it work and he's still healthy to this day.
Has anybody else had this happen?
Any clues for sure what it could've been?

 

[beth]

Red streaks or blotches on fish are almost always symptomatic of a bacterial infection.
The color changes in fish is a sign of stress. I've seen fish turn darker as well as lighter.

 

[hairtrigger]

Beth knows her stuff man. I have used full spectrum antibiotics to treat secondary bacterial infections before. That is always a good thing to try to be safe... that way you can treat some other possible issues at the same time. Now, I don't know many others who have tried antibiotics, but, they were successful for me. Glad your tang made it, they're beautiful.