tigerseyes,
I'm sorry to sound negative here but.....your profile indicates you have a 30 gal long. If that's the tank you plan to put the hippo in, please, please return him back to the lfs where you bought him. Tangs, particularly hippos shouldn't be put in anything smaller than a 75.
I had one in my 45....he was about 2" when I bought him and within 6 months he was 4-5". He developed a very bad case of ick which ultimately killed him and my other fish.
Hippos need lots and lots of room to swim....most people feel a 4 foot long tank is the minimum size for one of these. If they don't have enough room, they will become stressed and more than likely will become infected with ick.
If you chose to keep him now, maybe your lfs will agree to take him back and give you some credit a few months from now when he gets too big foryour tank.
Again, I'm sorry to throw this out to you, but don't want you to go through the heartbeak and expense I did.......
Jim