Cultured seahorses have become quite popular in the recent times, but in the reef tanks, they can thrive only in the environments with the right setup. They need pristine water quality, plenty of room to roam, assorted pods to graze in between meals, and a colorful natural setting that makes them feel right at home.
The perfect lighting:
Seahorses prefer low to moderate light levels rather than excessively bright light. They have corrugated retina that are rich in rods, which gives them excellent visual acuity under twilight conditions and low light levels in general. Seahorses do well under any type of lighting from metal halides to power compacts or VHO lighting, to daylight fluorescent tubes to ambient room light, providing shaded areas are available for them and overheating does not become a problem. Seahorses move into and out of the light often, seeking the comfort level that suits them at the moment. Seahorses do best at temperatures of around 73 degrees F to 75 degrees F. So avoiding temperature spikes above 80 degrees F is very important. Hippocampus barbouri, H. ingens, H. reidi, H. comes, H. Kuda are some examples of reef dwelling seahorses that prefer warmer water temperatures.
Water circulation:
Seahorses prefer moderate water movement, including some areas of brisk current, providing there are also sheltered and some areas of relatively slack water (comparatively low flow) they can move to when desired. Avoid dead spots and stagnant areas. Intake tubes should be shielded, siphon tubes should be equipped with filter baskets or screens. In the seahorse reef, overflows must be baffled and/or screened off, or the water flow should be adjusted sufficiently. Keep the water currents steady and unvarying so the seahorses can establish holding areas in the sheltered spots and low-flow zone without getting blindsided by unpredictable currents. Use small powerheads to create and direct current whenever needed. A properly positioned powerhead can bathe Acropora formations in a brisk water stream precisely, without generating too much water movement, elsewhere in the aquarium. But the powerheads can become deathtrapsfor seahorses if their intakes are not properly shielded or screened off. Carefully conceal the intakes amidst the rockwork where they will be completely inaccessible to seahorses, or otherwise, shield them, or screen them off with a coarse sponge prefilter.
Invertebrate compatibility:
Avoid any stinging animals with powerful nematocysts. This means fire corals Millepora spp. and anemones should be excluded from the seahorse reef, and any corals with polyps that feel sticky to touch should be used with discretion and only after careful planning. Small polyp stony corals are usually fine, but large polyp stony corals should be regarded with caution. The corals must be able to withstand being used as hitching posts by the seahorse from time to time. Avoid Tridacna clams and similar bivalve mollusks. Pre-treat your live rock with hypersaline bath to drive out any pests like fireworms, mantis shrimp or Aiptasia beforehand. 
Seahorse safe corals:
Soft corals (most mushroom anemones/corallimorpharians) have very little stinging ability and generally make good choices for a modified mini reef that includes seahorses. However avoid elephant ear mushroom anemone (Amplexidiscus fenestrafer). Seahorses also do well with zoanthids and colonial polyps in general. The SPS corals such as Acropora, Montipora, Pocillopora, Porites, Seriatopora, and Stylophora can also be tried. 
Animals to avoid:
Some invertebrates simply are not compatible with Seahorses and should be excluded from the seahorse reef. Sessile inverts like Millepora, anemones, and clams, as already mentioned and motile inverts like bristleworms and mantis shrimps. Highly toxic species like sea apples (Pseudocolochirus), cone shells and all cephalopods.
