I bought a baby red oscar and a baby albino tiger oscar, both the same size about 3 weeks ago(1 inch). I put a heater in the girlfriends goldfish tank to grow them on (no diseases). I have been feeding loads (to get them to grow quick) and a variety of food- maggots, small pond pellets, some slightly larger pond pellets, small hiraki pellets, medium hikari pellets, bloodworm, tetra prima and small pieces of prawn. As i have been feeding lots i have been doing 90% water changes every day (real easy on a small tank). The red oscar is a typical oscar and gobbles up the food as expected(full mouth etc). The problem is the albino, it doesnt eat no-where near what the red one does. The red oscar is growing much quicker than the albino, it is longer and bulkier. The albino is eating some, (its belly is not skinny or anything) but not much, it never fills its mouth up. Anyone experienced anything like this before and any ideas on getting the albino to eat more

Yes, when I bought my seven red Oscars, one of them didn't grow as much as the rest of them, he is still slightly smaller. I would say that as long as it is eating, you shouldn't really have anything to worry about. It's when the fish stop eating altogether and don't look right, that's when things might be wrong.

You could try feeding some beef heart and see if that helps in its growth.

Yes, I also had a similar thing with my young green terrors back then. One would not eat at all first (got to it again after I put it into a warmer tank), and later it ate never as much as the other 3 and grew slower as well. When I returned that one and 2 others to the shop later, they were all still bigger though than the ones that had stayed in the shop; guess they only fed the babies once daily there.

It sounds great what you're doing otherwise, and maggots are protein loaded, arent't they? (but yikes, lol)
I wouldn't worry much as Penn said already.

i think oscars might be racists, my red tigers do the same thing and my poor albinos never eat as much as the the reds.

i joke daily with the wife showing here how my tank has gone all politically incorrect on me.

as long as they get sum food in they should be ok my O's hv been like that now for a few months and the tables r starting to turn as my albinos are busy taking over.