Blue Tang - Need urgent help (see picture/video)

I'm so worried about my new Blue Tang! I received him/her 2 days ago (ordered online). Today I went to see my fish and it had some type of erosion under its fins.

I have 1 picture that is of reasonable quality: http://picasaweb.google.com/mysaltyf...04266289129650

It's hard for me to take photos, but I tried. I also took a video and posted it on youtube: YouTube - 9/19/09 - Blue tang problem

Please help me identify this. Is it ich? Something else? What should I do?

BTW, Yesterday I started Cuppermine treatment, so the water has half the treatment amount now (and the 2nd half is supposed to be added tomorrow)

I don't see any visible signs of ich, but certainly the behavior suggests that you need to keep a close eye on the fish. The white area that looks eroded is a very bad sign. I don't have much advice for you, unfortunately.

I am wondering why you ordered this fish online? The Blue Hippo Tang is readily available in almost every LFS, and you would have had your choice of selecting a healthy fish.

Even more of a concern to me is the Power Brown Tang that I saw swimming in that tank. Is this your fish also? They are extremely difficult to care for.

What could that eroded area be?

I put in a neon goby and it's helping to nibble on it. The blue tang likes it when the neon goby is eating away now.

Now it's rubbing its body on the PVC a lot... and I'm worried. And then it lies flat for the Goby to eat away.

The abrasion is just that... a flesh wound, probably a result of collection and shipping. There is likely a secondary bacterial infection, and probably some parasitical infection as well.

But he was fine yesterday. Maybe when the Goby started to eat away at his Ich, then the skin tore open?

If he was totally clear yesterday, it could easily be damage from territorial issues. Most fish establish territory and fight when the lights go out, and that Power Brown Tang is not going to be happy with another fish so closely related in a small quarantine size aquarium.