Last week I got a Royal Gramma from my LFS. After drip acclimating, I put the fish in the tank and it immediately went into hiding. I did a 50% water change 3 days later and I know the fish was still alive then. A couple days after this I saw my hermit crabs eating the dead Royal Gramma. About a day before this I noticed my Mandarin fish was gasping for breath. He was still eating and swimming around at this time so i figured he was just stressed from the water change. After the Gramma's death his gasping got worse, he stopped eating, and I noticed a couple semi transparent skin tags on him. When he continued to get worse I took him and my small clownfish out of my main tank into a quarantine tank. The clownfish seems to be doing fine but the mandarin has looked on the brink of death for several days. I finally decided to do a freshwater dip (I'm aware this is bad for the mandarin due to their slime coat) because I suspected gill flukes and figured he was going to die if I did nothing, so why not try. I did not see any parasites falling off him in the water. He is now back in the quarantine tank and is in bad shape. I figured he was a goner a couple of days ago. At this point I just want to figure out what is wrong with him so I can have a chance to save my clownfish if he falls ill. The mandarin is particularly hard to diagnose because his vivid coloration and thick mucus makes it hard to see bumps or spots on his skin. I did not notice any sort of bumps (ick or velvet) on the Royal Gramma before it died, but it also spent all its time hiding in the live rock so I never had a great look at it. The mandarin fish now has white in the iris of his eyes, they are not cloudy but a bright white. He is gasping at the bottom of the tank and doesn't look good. The freshwater dip did a number on his slime coat (again I was aware this would happen). Can anyone think of a diagnosis for him? I really don't want to lose my clownfish too.