Swirling fish

Images: 

Friday, my wife and I were snorkeling (not diving) Molasses Reef, buoy M-30, Key Largo, twenty-some-odd feet of water, bottom temperature probably 82 degrees, and we saw three groups of these fish swirling, not unlike a bait ball, but these fish were larger, probably six inches.  Anyone have a guess as to species?

Thank You,

Marty

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