Clownfish problem

[reefwars]

Originally Posted by monza

Don't you worry about the swimming stage of ICH being on/in your live rock your cycling back into your DT tank water from putting back into the sump?

(For reefwars) sorry a post snuck in between.

About as worried as I would be as if it came in on a random coral etc that's the reason why I keep the hypo so low while others keep it a little bit higher

[jtbadco]

Looks more like Brooklynela or Velvet to me from the pics. If it's Brook then you will see pieces of skin start to fall off and the Copper will not help. Formalin would work but it may be too late by the looks of the fish.
If its velvet then the Copper should do the trick, but you will need to remove and treat all of the livestock and leave the DT empty of fish for the treatment period.