General care and feeding of captive seahorses:
Three species of seahorse are commonly available in petstores. The 'common' seahorse, the brasilian seahorse, and the "dwarf" seahorse. The common is usually a dull yellow with black bands. The brasil is a little beauty, coming in vibrant yellow, orange, and red shades. The dwarf fish are usually brown, if they are true dwarf species (these stay under about 2 inches tall). However, many other species are sold as dwarves when they really are just juvenile animals.
**Note that the following guide is *just an overview* of caring for seahorses and more research should be done before rushing out and buying one of the charming little animals, as they aresome of the most difficult creatures to keep alive in captivity. **
-Buy an APPROPRIATE tank and cycle it FULLY. No 'oh sea horses are small, they can fit in a five gallon bowl'. None of that at ALL! see saltwater aquarium for instructions on choosing a tank and sending it through the nitrite cycle.
-Tank setup: seahorses need lots of live rock or limestone or coral skeletons or anything else they can hang on to with their prehensile tails. They do NOT like drifting around all the time with nothing to grasp.
-Companions. Very few fish are SAFE to keep with sea horses. Many species will attack them; but the largest cause of death in a mixed tank is starvation. Sea horses will NOT fight for their food, and if more agressive fish are there to consume all the food, the sea horses slowly starve to death. Mandarins and firefish are the fish that are both "safe" and prefer the same water conditions as sea horses. *Some* small gobys or blennys can be kept along as well, but it varies from species to species.
-Maitenance. Water change once ever two weeks! On the DOT! Most salt tanks need once a month to six weeks. Seahorses MUST be changed every two weeks.
-LIVE FOOD! Most seahorses will NOT eat anything but live food. A mix of brine shrimp and ghost shrimp is proper (brine only for very small seahorses). These animals MUST be fed at least twice, if not three times a day. For extra nutrients, brineshrimp can be soaked in phytoplex or microvert or any other plankton suppliment, while ghost shrimp can be fed plant-based flake or pellet food. The point if this latter step is this: the suppliments are highly nutritious for the sea horse, but almost no individuals will eat these things alone, for they are completely predatory and carnivorous in diet.
Keep in mind this is ONLY a start. If you really want a seahorse tank, DO YOUR HOMEWORK. Then node it