Quarantined Chromis: Looks like scales came off - what is it?

[robojet]

I easily captured my green chromis (already a bad sign). I separated him from my other fish (2 b&w clowns and a Flame Hawkfish). My husband noticed this spot on his side. It's the best photo I was able to get. I'm wondering if it's from getting bit (sometimes he irritates my female clown, but I've only seen her chase the chromis away), or if it's a disease - which I would really be concerned about because of my other fish. Any ideas?

Thanks!

 

[JHemdal]

It could be that it is just an injury. I can't see well in the photo, is its tail also damaged? If so, I would say it is physical damage from something.

On the other hand, it could be that it that is Uronema, a protozoan that gets into the fish's muslce layer and lives there, erupting through the scales in places. There is no real treatment for that once it erupts through the skin, but you could try chloroquine if you can find it locally.

Jay