wrong section, this should be in the marine area. anyway, seahorses are really really delicate and are NOT for beginners. they require much more than the basics from what i heard though its not impossible to keep them. you might want to do some research and ask around before attempting.
if you're looking at sea dragons, those that make your eyes pop eg. leafy sea dragons, you might wanna forget about them. they are a totally protected species and its illegal to keep them in a home aquarium as they face the risk of extinction