Everyone knows about anemones from the movie Finding Nemo. They are the habitat for Clownfish in the Pacific, but in the Caribbean, they are habitat for Pederson Cleaner Shrimp, Yellowline Arrow Crabs, Squat Anemone Shrimp and Spotted Cleaner Shrimp.
There are a number of different anemones in the waters and it is always a surprise to peer inside one to see who is hanging about. The most common are the Giant Anemone and the Corkscrew Anemone.
The long tentacles have a mix of toxins on them that aid the anemone to feed. This toxin will sting a human, sometimes not so bad, but sometimes lethally. So it is best to not touch anemones, or anything, underwater.