You'll find that they also like to perch on featherdusters and seaweed, and it makes for a nice looking addition to a seahorse reef. Regarding dried corals, try an amazon search. They have a vendor that specializes in dead, bleached, dried, mounted corals. Oh, they also like to perch on sponges and snails, which is fun to watch. Outta curiosity, what kind are you getting (seahorse, I mean)?
Bob