Sick Foxface need help!!

I got a foxface rabbit fish about 6 weeks ago and have it in a 29 gallon quarantine tank ever since I got him. I keep the salinity at 1.015 to help kill any saltwater diseases. But I noticed that his tail fin keeps deteriorating slowly so I thought he had fin rot, his fins are slightly red on the edges like their irritated. I've been treating the tank with Maracyn Oxy but that doesn't seem to be working. He still is eating great!! Please let me know if you've seen this thanks.

 

How are your parameters in the tank? Any Ammonia, etc. in there? I have seen this type of fin issue when water quality is poor - which is not uncommon in a QT. Also you may want to drop an airstone in there and make sure your o2 levels are high enough.

 

I believe you're stressing the fish with the SG value for no significant positive outcome. To kill marine ich you need an SG of 1.008. At 1.015 I do not believe you're treating anything. I am aware that there is a theory that keeping fish at lower SG is therapeutic with regard to parasites I do not see the value in keeping the SG at 1.015.
Is the fish getting enough marine algae and variety of foods?

 

Yes he is getting a variety of foods an green algae.