how big is your oscar, as a baby your 29gal is fine. He will need a 75+ gal tank though. Mine is in a 130gal. As for tankmates, when you get a larger tank, Oscars do pretty good with other fish of the same size and temperment. Mine shares a tank with a Black Crappie and a White Bass. And all 3 of them shoal together in the tank, its actually quite funny to watch, but anyway, start saving for a bigger tank, check craigslist, you can score big tanks for very little. Good luck.