They both get around the same size. While oscars are put in tanks 75+ gallons, goldfish are being put in bowls when they grow to 14'' at the most and are just as dirty as oscars? Isn't that stupid?!?!?
all people dont put oscars in huge tanks. in fact, oscars are in 10 gallon tanks just as much as goldfish are in bowls. sometimes they are in the same tank.
people do buy oscars to put them in 10G tanks. the oscars you see in stores are usually at least 2-3 inches and look larger than your average feeder goldfish or fancy goldfish.