CichlidFish.com - Fish That Think.

I have 2 Oscars, both are pretty big, about 6 - 8 in. Both are male, I have them in a 55 gal tank.
I have had the first Oscar for almost three years now, and the 2nd about 1 1/2 so I do not want to see them perish. The smaller one grew but was kinda discolored, discolored meaning maybe a grayish color, not the normal black and orange that you would normally see. I figured it was due to having 2 males and 1 dominates the other etc etc, well as of a week ago I noticed the younger Oscar laying on its side, like it was dying, scales were not moving much, so i just shut the tank light and was just waiting for it to die peacefully, well few hours later i go back to the tank to feed the remaining Oscar and to my suprise both fish are swimming around like nothing happend. Today i wake up and notice that the sickly fish is looking worse then ever, discolored all over its body, looks white. It is spreading onto the larger Oscar but not as much.
I'm confused and don't know what to do, I will take anything you can tell me and try it.
Thank you, Mike......  .

First things first.

check water params, without an Ammonia, Nitrates and Nitrites readings we cant make a decent stab at Iding the problem.

Oscars change their colour due to their mood. Id start by doing an immediate water change, about 30% ideally.

If the "Discolouring" is fuzzy, then treat the tank for a fungal infection.

Id also suggest putting a divider into the tank for the time being. Chances are your Oscars (both male) are fighting over territory.

Get some water tests up here, and well be able to see what the problem is.

Cheers
Craig

Another deal with Osacars is they SLEEP on their sides.. So he was actually resting.. As they can't close their eyes, they kind of sink to the bottom of the tank instead of float to the top.. dis color now is a different matter.. AS Craig says, check the pH, ammonia and nitrite.. ANY reading on this is a BAD deal.. IF they are fine, then a good tank and filter cleaning wil right the the water conditions back to normal.. U might want to do more OUT/IN on your water changes to increase the delution of toxic gasses.. A good VAC with a water change on a 55 gal with OSCARS is about 20 gal WEEKLY.. CLEAN THE FILTERS TOO at the same time or U just waste a good water change as the filter wil pump back in the harboring uneaten food and waste back into the tank.. Their colors should come back in hours...

Kind of late here as the first post was on Dec 14..  So how are the now?? 

Discolouration can also be due to food and hormones. I have black and grey juvenile tiged oscars coming through my work, they are just fed a different diet and something is altered with hormones.

when oscars are on their side or hanging around the bottom of a tank, it's because they are nothing but big sooky babies. If he's being picked on he'll just be hanging around down there. If you're still worried try a preventative (half dose) of white spot remedy (I think you guys call it Ich???) every two days for a week just in case he's being stressed, it could be ich or it could be velvet, which is a worse form of it, I don't know if you have the same name for it, but it looks like they are coated in velvet.