Well, fish shed their
slime coat for a variety of reasons.
Before we get into that.
What is the Tank Temp and what has it been recently?
What are the Nirtrates, Ammonia, etc.
What is the Salinity at?
Have you added anything recently?
What else is in the tank?
Why are the lights off?
Have you medicated it with anything?
Was there anything funny looking about the clown when you purchased it?
How did you cycle the tank? Live rock, damsels, other?
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It could be velvet? Or Ocidieum (spelling?)
Could be stress only.
6 weeks is a very new tank. might have not been ready for a fish depending on how you cycled and how much you feed.
Anwser the questions above and we;ll do our best to help you out.
-Hank