I wouldn't.. speaking from experience. I was the same way as you when I first got into "reef" fish. I just had to have a yellow tang.. and I knew better but I still bought a baby for my 29G and told myself "I will return it when it outgrows the tank".. well.. didn't work out so well, I waited a little too long and the tang got really stressed out and got its fins all nipped off by my maroon clown.. this was within 6 months. Tangs grow very fast and will outgrow a 29G in no time, plus they will be extremely stressed out the entire time in such a small tank, even a small baby tang.