Ack, What's Wrong With My Oscar?

[Conqueror]

OK, there's something definitely wrong with my oscar...

Here's what he looked like a week ago (click for hi-res):



Nice bright red with a dark-colored back.

I walked into my room yesterday and my jaw dropped... in the last three days he has turned into this:

As you can see his back has turned an ugly pale, grey/purple color, and he's lost a number of scales on his ventral side. The large white spots you see are on the glass, not the fish. He has no signs of ich that I can tell (ie, salt-grain white spots on his fins). There is a newish resident in the tank, a striped peacock eel, which I'm having trouble feeding (it won't eat). Is it possible that the eel is nipping scales off the oscar, which has caused a secondary infection of some sort? My pleco also has signs of such an attack, he has a new battle scar on his back which wasn't there a week ago. The tank is 55g US. I don't want my Oscar to die, but I also want to keep the eel. If this is the root of the problem, how do I get the eel to eat and leave the others alone? Help!

CQ

 

[aardvarkfromspace]

probably hungry eel.. what are you tryin to feed it?

 

[Conqueror]

I'm trying to feed him frozen bloodworms. That's what he was supposedly eating at the store where he was purchased. First I tried the turkey baster method with thawed worms, but the oscar would always eat them first, even if I squirted them directly onto the eel's face. He would just sit there looking at them. Last night I put a frozen block of worms under his cave, thinking maybe they would thaw there and he would reach them first. The light's not on yet so I can't see if he ate them (of course if they're gone, the pleco might be the suspect too, cause he can fit in the cave).

CQ

 

[aardvarkfromspace]

Might try turning the lights out.. wait 15 mins.. then drop some catfish/bottomfeeder pellets in the tank.. that's the only way I can get my ID sharks and bichir to eat... when the other fish are sleeping