Something up with my damsel's eye

[AdamHorton]

Just got home today and saw one of my damsel fish and there's something up with his eye. Here are the best pictures I could get:

http://www.adamhorton.com/files/eye01.jpg
http://www.adamhorton.com/files/eye02.jpg
http://www.adamhorton.com/files/eye03.jpg

Params:

Specific Gravity: 1.023 (a little lower than the 1.025 I try to keep it at but still within range, I believe?)
Ammonia: 0
Nitrite: 0
Nitrate: 20 ppm, maybe a little bit above, couldn't be more than 30 ppm.

I did a water change this weekend, part of the 10% bi-weekly PWC schedule I use. The last time I distinctly remember seeing this fish looking normally was last night, there were no problems at all then. Right now, the only thing out of the ordinary is the eye, there is no aggression beyond what is normal, and he's behaving the same as he always does.

Here's a page with an updated description of the tank and all of its specs:

Tank Specs | Adam's Flog

In case it's relevant, the tank was moved about 4.5 months ago with no casualties. I didn't see any traces of a mini-cycle or anything. This particular fish was one of five that survived my previous tank crash. That was about two years ago, and during that process he was undoubtedly exposed to whatever caused the tank to crash (I still don't know what it is) as well as being exposed to the ammonia/nitrite that happened when he was moved to a QT for a couple of months while I started from scratch.

Finally, the only other disease-related thing that's ever happened in this tank is detailed in this thread:

http://www.aquariumadvice.com/forums/f16/something-on-bangai-cardinals-lip-135485.html

I've had tons of success with this tank and I think I've listed everything that could possibly be relevant here. What could be wrong with this guy? It may get interesting if I have to QT him, I don't know if I could catch him without tearing the whole tank apart, and even then I have two tangs I'm QTing right now (making sure they don't have ich before I put them in the tank).

Thanks for your help.

 

[Innovator]

The damsels eye seems distended "pop-eye" and your Cardinal's lip does have abrasion, both of which could be treated with an anti-bacterial such as Nitrofurazone in a QT.

 

[AdamHorton]

I should have mentioned, the cardinals are fine now, that was from a while ago.

This morning the lights weren't on, but I noticed the water was kind of cloudy in the tank. Maybe it just looked that way because it was dark. I'll check it again when I get home tonight and the lights are back on.

EDIT - turns out the water isn't cloudy. My bad, please disregard.

I read up a little on that condition, and it says that since only one eye of one fish is affected, it's probably due to trauma and that netting the fish to put it in a QT will probably cause more harm than good. I think what that means is that I'll need to keep a really close eye on this tank and make sure he starts to recover, as well as the other fish so I can make sure nobody else shows signs of infection.

I haven't noticed any discoloration yet, but I also read that blindness is possible, particularly if the eye turns gray. My guess is that he can't see out of that eye right now, judging from the way he swims. I hope he gets his sight back...