Oscars grow up to 14", give or take depending on the individual, and a 55 is 48x12". Most ppl recommend at least a 75 for a single species since the 18" depth gives the fish space to face out of the tank and turn around more comfortably.
Yeah, just keep the decor to a minimum, no plants, and avoid anything with a rough surface or a sharp edge. Even being little they still run into everything and find ways to hurt themselves if they dont have enough space.
the fish guy commented on my post! hahaha but no worries fish guy, my parents will buy a bigger tank for me when the time comes, i was just curious if the 55 was going to suit him or not. thanks for the replies