There is nothing to Fear, but Fear its self!
A healthy respect for marine life is good. Fear, not so much. If you are like most divers once you are enjoying your first view of an awesome reef, or swim through a bait ball, or hang out with a Jewfish, you will realize that there is very little to fear UW from the marine life.
There are a couple of exceptions. First is things that don't look harmful, but are. Fire Coral is a good example. Don't touch stuff especially if you don't know what it is, but that's a good rule to follow period. Learn about what is dangerous UW, like Scorpion Fish, and other marine life with built-in protection.
The second are Bull Sharks. Respect them, and study their behavior so that if you do come into contact with them you can recognize aggression. They generally don't attack divers, but there are exceptions. I'm not aware of divers in FL getting attacked, but divers have been killed by Bull Sharks in S. Africa, and they are the #1 human attacking shark based on what I've read.
Another thing you need to be aware of is if this fear grows once you are UW. Your biggest fear should be of yourself. Panicked divers can die. Take your OW class seriously, get your basic skills down as best you can, and enjoy your new hobby.
WARNING, diving is addictive, and can lead to a serious condition known as DD (Diving Disorder). DD can lead to massive gear spending, entire weekends spent UW, and in severe cases waking up in the bathtub with your regulator in your mouth!