Just get a 125g and be done with it ;)
Sharks for example, need to swim around in order to breath. if you stick it in a long tank, it has swimming room. Stick it in a tall tank of the same volume but shorter length, it has less swim room because by the time it gets its swimming groove on, it hits the end of the tank.
I'm not posing a generalized idea here, because some creatures do prefer a taller tank because they do a lot of up and down swimming like seahorses...but if we're talking about a fish that loves to swim around, it would be happier with more horizontal swimming room. I know some of you have placed tangs in smaller tanks, and have had luck, Good for you. But me, I prefer to follow the guidelines. I was fine living in a small apartment. But once I kept getting bigger and bigger places to live, I was much happier. That's just me.