First things first, you need a Florida saltwater recreational fishing license.
Those can be obtained here.
Also of note is the ornamental bag limits page and IMP (indigenous marine protected) listings. Don't be collecting those Bahama stars!
After any number of days collecting, a single person can only have in their possession a total of 40 animals. That means a maximum of 20 neon gobies or blue chromis. Some fish, like angelfish, have special limits. I think that you can only have a maximum of 10.
There will be times when you find a tiny blue angelfish but realize that minimum size is 1.75 inches. Our masks make things look bigger but small (<1") angels and especially butterflies are difficult to get eating and starve very quickly. Also, realize that things like snails and hermit crabs count towards your bag limit.