The seahorse is by far one of the most interesting fish the hobby has to offer. Available in sizes from the very small dwarfs, who barely reach 2 inches, some of the huge Pacific seahorses can be a foot long. Pressures on seahorses in the wild, mostly from the Chinese medicine industry (and not the pet trade), have finally resulted in their being listed on Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). So now, all seahorses you find in your local fish stores should be aquacultured. Commercially raised seahorses are usually strong and disease-free, and they come already trained to eat frozen foods, primarily enriched Mysisshrimp.
Seahorses do best in an aquarium dedicated primarily to them, as they do not like the high light levels and water movement of reef tanks, and they cannot really compete for food with other faster fish. The ideal tank setup for seahorses is very simple, with live rock and a protein skimmer, along with frequent water changes. Water movement must be very gentle. It is most important that you provide the seahorses with plenty of sturdy fixed places where they can perch by wrapping their prehensile tails around the perches.
If conditions are to their liking, and they are well fed, seahorses will readily breed in the aquarium. The pair rise through the water column and the female deposits the eggs into the pouch that the male has; he broods the babies in his pouch, and eventually live baby seahorses are ejected, perfect little replicas of their parents, and are able to eat baby brine shrimp.