Yellow Tang with Red Spots

[robert d]

I have a tank with a yellow tang in it. she looks a little under the weather. She is eating fine but near her tail there are large red spots that look like bruises. Also the line that runs down each side has turned red like the color of blood. Also on her face she has these same blotches but smaller.
Any help is very appreciated. Thanks in Advance.
-Robert

 

[robert d]

thank you.
I am not sure how he would have gotten it. The only thing that I have done differently is added an algae killer that was recommended by the pet store I get all of my supplies from. The product is called ChemiClean and it is supposed to get rid of the red algae problems I have been having. The tank has been established for at least 4 months without any incidents. The only other fish that match her size is a Koran Angel fish that we have that is just a little bigger. The Koran is very non-aggressive. he is always hiding somewhere. Other than that ammonia is ok salt was a little low. I just checked it and it is at 1.018. Could that be the cause? Ph is fine too.....
ANy additional ideas are appreciated.
-Robert
PS I've never done a hospital tank. How big does it need to be? What shoudl I use? Should it have a bubbler or something to introduce oxygen?

 

[beth]

What are your nitrite, nitrate and phosphate readings. Tangs are very sensitive to organics in the water.