Wow, you've got a ton of threads on this subject. I say
NO....because you can't keep your mind made up from lunchtime till dinnertime as to which fish you want to keep and where

I'm not
trying to be mean or picky, but you've just got to decide on something and leave it be. That 55 g isn't big enough for an Oscar UNLESS you're willing to consistanly (
until you're 25 yrs old) do bi-weekly water changes. We all have to have the maturity not to get animals we can't/won't/aren't willing to-take care of. Even at 14 or 15 yrs of age you're capable of that. Don't get them if you don't-at that moment-have a place for them.
This is the problem. Don't 'plan' on things. Get what you need BEFORE you get the fish.