I used to live in FLA, and we did go to Miami last yr. Not a whole lot of fish experiences that I can think of. I would head down to marathon to the sea turtle farm/rescue. There was also a porpoise training facility down there somewhere.
You could check out Jungle Island? Also, non animal related, take a sight seeing cruise in Key Biscayne and tour around some of the islands and check out movie stars homes. Had a great time doing that. We also went to the giant natural made pool in Coral Gables. Dont know the name, but it was cool to see and swim in.
Very cold!!!
Art