Lighting a seahorse aquarium is less complicated than filtration. Seahorses have excellent eyesight. The only health related issue that seahorses have regarding lights is the heat output. As long as the water temperature stays below 75 degrees, any aquarium light fixture can work. These days most seahorse keepers use LEDs or T5s. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.