How aggressive is, to me, an unanswerable question. They are sturgeonfish but every one has their own personality. Mine shows no aggression at all.How aggressive are they? You don’t think he can be in a 4’ 90 for long do you? Just spit ballin. I’ve chosen not to have tangs in my tank atm but…
Mine is in the don't start no crap, won't be no crap world.
They don't start out big. A smaller model could definitely live in a 4' tank for a while but not a long time. I've seen a bunch of 2-3" available at shops around me.