Black Fish

[nate9]

i woke up this morning after buying a yellow tailed damsel yesterday to find the damsels entire body has turned black except the tail! what should i do and has anyone ever heard of this?

 

[WILDER]

Don't know anything on these fish so i would post in the right section of the forum, you will get more help, black patches can be ammonia burns that are healing but if it turned all black i don't know, i would post yours stats as well in ammonia,nitrite,nitrate,and ph.
You did climatise the fish properly, what was the ph of the store to your tank.