This is an interesting tree to me since I don't live in the coastal area. The root system is cool. There are other type of mangroves that send their roots up like little snorkel tubes (black mangrove), but this one sends them down (red mangrove).
The mangrove tree Tampa, FL
It is a pipefish of some kind for sure . A little googling and I believe it is a gulf pipefish .
The mangroves are very important in that they provide habitat for many aquatic animals as well as erosion control for beaches. They shed the salt from the water through the underside of their leaves - you can even have a taste!