Seeing seahorses in St. Thomas snorkelling?

[Appygirl]

Does anyone know if its possible to sea seahorses in St. Thomas, prefer snorkelling but would be open to scuba diving. Years ago a woman who dove out of the same shop I used told me there were seahorses all over a dock she dove in St. John. I'm hoping I might find something similar in St. Thomas. I've always wanted to sea a seahorse that's not in an aqaurium tank. I realize there is no guarantee of seeing any sea life on a dive but was hoping there might be somewhere in St. Thomas where there's a good chance I might spot one. Prefer snorkelling but if the only seahorse sightings or more likely by scuba diving I'm open to that too. Or even that underwater scooter thing I saw on another thread. Are equipment rentals reasonable/easy to locate? Might bring my mask and snorkel but the fins are huge, and well we all know about flying with luggage and keeping things to a minimum! We'll be on the Emerald Princess if the cruise line makes a difference but we prefer not to stick with a ship sponsored excursion.