I don't think you can keep some sharks in that 125 full grown, you'd hafe to keep them as juveniles or around middle age.I'd get a banded cat shark, you could put big angels in there, a lionfish, and tangs. NO TRIGGERFISH!
NONE! I mean, ok, you could probably keep something small, a horn shark, maybe a banded shark... but think about it... a 3 foot long shark in a 125 gal tank?!?!? I say minimum for any shark to be happy and healty is 300gal.