I don't have a photo to post righ now but one of my four baby oscars (2-3") has a really big stomach. He is the largest, growing extremely fast but his stomach looks abnormal. At first I thought it was because he eats the most but I am too sure. Maybe in the morning I will have a better idea. Any clues as to what it could be?

[Temp. 79.3 F.]
[Amonia 0 Nitrate 0 Nitrite 13]

photo would be helpful so if you can get one, please post it. Okay, swollen abdomens can be a result of many factors, I'm sorry but I can't give you a conclusive answer. It could be parasitic infestation, bacterial infection, organ disease, and quite a few other things. I would suggest that you keep an eye on the fish and see if it gets any bigger, or indeed starts reducing in size. If it stays that size then it could be something more serious. If the fish are still eating then it's obviously not too ill. If the fish does stop eating and it has an abnormally large stomach then I'm afraid that could be a very serious situation which the fish may not survive. I've had this in more than one occasion and have lost fish with this condition.

Fingers crossed that isn't anything too serious. Try feeding the fish peas, there is an off chance it could be constipation.

No real idea, does everything else seem fine otherwise?
Like the scales looking smooth and normal feces etc.?

Let's hope he's just extraordinary greedy ... if that is possible with Oscars Think with some pellets, it is that they expand still in the stomach if eating too many too fast, pre-soaking them is a good idea then.

EDIT: And once again Penn beat me to it, lol.

He is greedy it looks a little better today but I will just keep an eye on it. I do have 1 more question. Do different types of oscars grow faster. This one was suppose to be a lemon oscar he is starting to look more and more like one but he is growing faster then any other oscar I have ever owned, over and inch this last month.

He may be constipated. I never used to feed my fish on a sunday, now they get peas (if they want them, some wont eat them). Peas help digestion and if they dont eat them then going without food clears them out

All oscar are different and they grow at different rates