BALLYHOO!
I think the beak fish with their beaks on the bottom are ballyhoo. I don't know if they are one species or just a generic body format, but they are a pretty common appearance in SW even up to North Carolina and a great baitfish. Is this the same fish, just adapted to light brackish?
BTW, the cave fish are really neat. If you ever get a chance to see the cenotes (mexican sinkhole caves), they are amazing.
Brandon