The slender seahorse or longsnout seahorse (not to be confused with the Long-snouted seahorse), (Hippocampus reidi) is a species of fish in the Syngnathidae family. 
The slender seahorse typically grows to be approximately 6.8 inches long (17.5 centimeters). Males and females are easily distinguished due to their bright colors. Males are usually orange, while the females are yellow. However, both males an females may have brown or white spots placed sporadically upon their body. These spots may also change into a pink or white color during the courtship period. 
Habitat and Distribution
The slender seahorse has been found at depths of 55 meters. The smaller the size of the slender seahorse, the greater the chance that they will be in shallower waters compared to more mature ones. Slender seahorses have an affinity for coral reefs and sea grass beds and can be found on gorgonian coral, seagrass, mangroves and Sargassum. The slender seahorse is native to the following countries: Bahamas, Barbados, Belize, Bermuda, Brazil, Colombia, Cuba, Grenada, Haiti, Jamaica, Panama, United States (Florida and North Carolina), and Venezuela.  They inhabit subtropical regions, ranging from 29 degrees North to 25 degrees South and 133 degrees West to 40 degrees West. 
- ^ a b Froese, R.; Pauly, D. (6 October 2010). "FishBase".
- ^ a b "Slender seahorse". Monterey Bay Aquarium.
- ^ Project Seahorse. [www.icunredlist.org "IUCN List of Threatened Species Hippocampus Reidi"].