Originally posted by Dogstar
the naso needs a biger tank than a blue cause they like to burn the jets but there more hardy once aclimated but can be picky as far as feeding. Blues are pretty lazy as far as tangs go so a smaller tank works rather than the naso but they get stressed reel easy even after you had them a while. Blues will eat anything you give them thus hippo. So its a draw. I have two hippos and zero nasos.
I think dogstar summed it up the best as far as the actual fish goes. The points he made were:
1) tank size - hippo over naso
2) eating - hippo a little more so than the naso (IMO)
3) hardiness - tangs are a tang. Yes, hippo's are ich magnets, but that shouldn't be an issue. Now don't get me wrong, ich is NEVER a good thing, but come on, if you are getting a tang, you better have good water quality. Maybe the fact that hippo's are a little more prone to sickness is a motivator to keep your tank clean. It's not like it's impossible. Look how many people have success with hippo tangs. You just need to keep up with your water quality. (Plus, naso's are usually a lot more healthier and hardier IMO when they are a little larger anyway -and a 90 can't afford a "larger naso".
All signs point to the hippo. Now maybe if you had a 200 or so like some of these guys that responded, I would give a different answer, but with your circumstances, I would go with the hippo. Then, when you do decide to get the 200 or so gallon tank like all of us eventually do, you will be able to get the larger naso and he will fit right in.