Hey Larah,
Olive snails are cool. They are pretty. They are sleek. They can fly (sort of). They hide a lot. They are good scavengers. And they will attack prey up to about THREE TIMES their own size, and with any luck, will kill things almost that big. I kept several different species, but my best story is about Oliva sericea. (I usually tell the abridged version, but I'll give you the longer version.) I brought one home and threw him in the tank, and he immediately went underground. I didn't see him again for weeks, and decided he wasn't going to make a very exciting tank resident. Eventually, I brought home a bunch of conchs and dropped them in the tank, which changed things a little. That night, after I had turned out the light, I started hearing "plink, plink-plink, plink...plinkplinkplink..." and thought, what the heck is going on in my tank. I went over and looked, and everything in the tank was in panic mode. All of the small conchs, Strombus gibberulus, Strombus mutabilis, and Strombus luhuanus (which were bigger than the olive) were all jumping and bouncing off the tank walls. The fish were swimming rapid circles, and there on the bottom was the Oliva sericea, "flapping" the sides of his foot and flying?, not crawling, around the tank. If I gave a speed estimate, I'd say he was moving about ten times as fast as an olive normally crawls, maybe more. I watched him curl the front of his foot, and grab a big Strombus luhuanus, lifting it above his shell, then humped over and tried to stuff it into the pocket formed by the slit down the bottom of his foot. The big conch managed to kick loose, and the olive resumed chasing the smaller ones until he caught one, engulfed it, and dove underground. A few minutes later, the conch resurfaced, apparently unharmed, and the olive came back out and caught another one, and this time he didn't resurface. It took a few days, but he eventually killed and ate every conch in my tank. He was a killing machine, until my Conus textile caught him and ate him.
I don't know how the ones from Florida compare, but I suspect they might be pretty effective killers, too? The smaller species might be less of a threat.
Cheers,
Don