Sick Fish

[omoreno]

One of my yellowtail damsel has developed this white, crustlike growth on the edge of his right gill(see attachment). this is a new tank about 2 months old. I currently have 4 turbos, 3 scarlet crabs, 2 brittle starts, 2 yellowtail damsels(1 sick), and 1 fire goby. All fish are feeding fine and are not scratching against any surface however, I do notice that the bigger damsel shows aggression to the smaller damsel(the sick one). Also for the first 6 weeks my salinity was really high(1.028), I know, the reason I found this out was because about 2 weeks ago I bought a refractometer and found my junk(i could choose a more word) Deep 6 hydrometer was off(high) by .004. I have since bought down my salinity to about 1.023-.024. Any insight on white growth, would be appreciated.

Tank: 55 gal, 50# LR, 2 PH, Aquac Skimmer, 55# LS, Emporer 400(more for flow and surface agitation. 5% RO water change every 2 weeks.
Amm: 0
Nitrites: 0
Nitrates: 0
PH: 8.2

Sorry for the long post wanted to give as many details as possible.

[PeeJ]

Looks like ich to me.

[RobertG]

Salinity could have him STRESSED , looks lot like ich. Or the bully maybe. Did you put these guys in together ? I assume you did. If not,would think bully.