I reccommend that anyone new to the marine hobby, stay far, far away from seahorses. Far away. Far far away. I had a talk with the Curator of Fish and Invert at the aquarium not far from my home that has a whole seahorse room, and all he could do was bitch about how each speices had one specific type of food that had to be literally dumped in front of its nose to eat, and how delicate and fragil and what a hard time they were having with them, let alone trying to breed them.
Magazine articles are always good for points of interest, but they always make out something really difficult to be really easy. Be smart, don't get anything fancy. Those things are definately wild caught, and there is no reliable information about their populations to insure that the pet trade isn't depleating them. Exotic seahorses aren't worth the headache unless you want to seriously dedicate yourself to an animal.
But on the flip side, I've had lots of luck with local water seahorses. Mostly lined seahorses (Hippocampus erectus), and northern pipefish (Syngathus fuscus). Sometimes they'd come up in the sein nets along the beaches. Where I used to work, we had a trio of them in a 20 gallon long tank. Decorations were a few hunks of coral, a lava rock, and plastic pants. They'd ancor to anything. We fed them live mysid shrips and artimia naupil from a 1mm pipet. After awhile, they actually would swim to the glass to get fed, and "beg" which made it easy to plop food in front of their faces. But they aren't the strongest swimmers in the world, and would give up the chase after four or five shirmp. One of them had even been found wounded on the beach. It healed back up, but never regrew its dorsal fin. We were all suprised, and pleased.
When I lived in FL, we actually had a Sargassum seahorse, or seadragon, that we found in a matt of seaweed. The whole mess was transported into a local water tank. But we also had plankton trawls that provided plenty of little live food for him. I've never tried seahorses on fake stuff. I'm sure a starved one would eat anything that drifts in front of its snout.
If you have a local water marine tank, and the availability to sein net, then go ahead and try seahorses. They don't like strong currents, but do need gentle circulation from a powerhead. And aged, already cycled water, is the best to use for them. But I wouldn't buy them from a LFS, even if they are H. erectus. Seahorses stress out very, very easily, which is probably why lots of people don't have luck with them. First they get ripped from their happy homes, then bagged and boxed and shipped to a wholesaler who dumps them in who knows what conditions, then bagged and boxed and shipped to a retailer, who dumps them in who knows what conditions. Not good for seahorses, not good at all. So you're already purchasing a fish that is not a happy camper.
~~Colesea