My question is, how can Sonic breathe in space? he's been super sonic and not super sonic and was able to survive in space.
how's this possible? does he not need oxygen?

He needs Oxygen. The only time he doesn't is in a cartoon. In the game, no oxygen = no Sonic

Of course he needs Oxygen, but you know how video games and cartoons are...

Maybe he stores air in his cheeks like hamsters do with food. Lol. But then again, he never does that in the games. I know! he entered 'cheat mode' in the TV episodes... Yeah, that'll explain it

lol.. cheats...

Not necessarily. I recall that in Sonic Adventure 2, Sonic went into space quite a few times, such as in the Crazy Gadget level and when fighting the Final Hazard.

Maybe anthros like the Sonic characters can survive without oxygen for certain amounts of time, kind of like whales or dolphins.

Oddly enough, (On the topic of Sonic needing oxygen) found a glitchy area in Cannon's Core of SA2B while playing as Sonic. If time gets frozen forever, and sonic starts running down the slide, he get's stuck at a certain point and drowns. So does that mean SEGA intended there to be a stage where Sonic must travel underwater?

On the topic of the Space thing, there is no known logic in the cartoons/comics, compared to the games when it comes to those things.....

He can drown in water, but he can't suffocate in space. Thats hilarious.

Yes, Sonic does need oxygen. I recall in Sonic adventure DX where he appeared to be breathing. As for the ARK in Sonic Adventure 2, I read somewhere that somehow the ARK has some sort of dome around it, so he could be able to breathe like normal. It's most notable that Sonic breathes when in Sonic the hedgehog 3 when you're underwater for too long, Sonic drowns.

tut tut.
crazy Sonic Team.