Pinfish and Sea bream are common around the Florida Keys. They make ok live baits but probably not the best. Larger aggressive fish will eat them, pretty eagerly such as Tarpon, sharks, grouper, bluefish and jacks. They can usually be purchased at local bait shops for around a buck a piece, they are hardy and will live in pocket with an aerator no problem.
But most people don’t buy them from bait shops, they are really easy to catch anywhere there is thick sea grass, especially on the bay side. All you do to catch pinfish is throw a block of chum in the water around the grass and wait a little bit. If none show up in 10 minutes move. You will see them running around all over in the chum slick. For the most part they are masters at avoiding cast nets, except maybe if you are out in Florida Bay where they get so thick it looks like you can walk on them. Most people just use a small hook and a small piece of bait; you just free line the bait into the chum slick and bam you got pinfish.