foxface and copperbanded butterfly sick

Ok, I recently bought a copperbanded butterfly fish a bit ago from a reputable lfs that quarantines fish for 2weeks before putting out to sell. I added one of their fish to my tank and now a bit later the copperband has a white thing on his tail and it is bigger than an ich cyst. My foxface as well has brownish black spots on just one side and a few tiny ones on his fin, are these a sign of marine velvet?!

 

Without pictures it's difficult to tell for sure what they've got, but here are my guesses:

Copperband:
My guess here is Lymphocystis which is a viral infection. This is the equivalent of a cold and will usually clear up with good diet and water quality. Typically it looks like a fuzzy white spot which is, as you've described, bigger than an ich spot. This is not something to worry about at all if your tank is in good condition. I've never seen this have lasting effects, but then I keep my tanks in good order so it has a chance to clear.

Foxface:
Tough to say for sure, but I'm wondering if it could be Turbellarian, which is commonly referred to as Black Spot Disease or Black Ich. I don't know much about this disease as I've never had a fish with it. All I know is what I've read on the web.

What you've described doesn't sound to me at all like Marine Velvet. Be glad too. I've lost entire tanks to the disease. It is, in my experience, the nastiest of all marine diseases. Mine came in on a piece of live rock and within days everything except a damsel was dead. That was 12 years ago and luckily I haven't seen it since.

 

Good news, the copperband cleared up within a day So happy about that, and as for the foxface I think something may have been nipping at him or he got scraped on some rockwork because it is only in a nickle or bit bigger area and not anywhere else. They even look like bite marks.

 

Do yourself a favor and not make my mistake, keep a close eye on the new addition- any signs of illness after this clears- remove him ASAP.

 

Heres a pic of the foxface, and the only new addition was the copperbanded

 

That is not Black Spot. It could potentially be a bacterial infection, but more likely looks like an injury/sting. Do you have any stinging corals or anenomies in the tank? He could have gotten stung or he could have been freaking out a little bit with the new addition and scraped against a piece of rock or coral while acting like an idiot. Foxfaces are not as idiotic as Yellow Tangs, but they are a close second.

Other questions:

Is the Foxface exhibiting any other symptoms (e.g. not eating, not swimming well, scratching on rocks, etc.)?

Has the area been constant since you first saw it or is it growing?