Here's my pretty little girl, shes about 5.5 inches!

nice set up but small for her.
while in that small tank, pls keep the water
under check & feed sparingly to stunt growth.
hope you could switch the tank a.s.a.p. to make
her happy.

i change 10% of the water 3x a week and she should be ok on size for 4 months but if she gets stressed i have an extra 40 breeder but no stand. she is pretty much spoiled with her diet cuz she gets 6 different kinds of food regularly, i cant wait for my 55!

from what i can see of your o's pic he looks really nice.

getting to your tank size- i dont think that you have another four months to wait for a larger tank. oscar grow at about 1 inch a month for the fisrt 7 months or so then slow down on their growth a bit. another 4 month will put your oscar at about 3 inches bigger in length and girth and that will be pushing the limits of a 20. your 10% water changes 3x a week is good for now but i suggest you start using a water testing kit to determine if its still enough or if you should increase it.
personally i would put him in your breeder tank until your 55 arrives.

just my opinion

thanks for that! I do water tests at least twice a week cuz i just bring it to work with me, petsmart does have its perks!