I hope this statement from
@eatbreakfast is still true. =)
I have a pair or coris on day 5 of copper power at 2.0. One of the two is out and about just fine. the 2nd and larger one is surprisingly still in the small container of sand I put in the QT for them. I know they will hide thus I didn't go looking for the larger one until this morning. Stirring him did get him out of the sand for about 10 seconds before he went back inside. Then off to research move because he's been hiding for 5 days. .Does that mean he hasn't really been medicate for 5 days?
There is no flow that would push the medicated water into the sand container aside from the smaller one going into the same container at night to sleep. I'm questioning the treatment of the copper and other meds that may not be effectively getting into the sand container.
I did noticed red marks where the fins meet the body. He wasn't out long enough for me to take a photo, but it was on both sides. Maybe just sand irritation. I just hope there is enough meds getting into the sand...