There are over 30 recognized Hippocampus genus member seahorses that inhabit tropical, sub-tropical and temperate waters around the world, but only a handful of species are typically encountered in the aquarium trade. From the few wild and numerous tank-bred specimens one finds for sale, H. kuda and erectus are at the top of the list of the most common species of seahorses that are seen in aquariums.
The Brazilian Seahorse (Hippocampus reidi) was initially introduced into the aquarium trade after being imported from Brazil in the past, this is actually an Atlantic Ocean species that occurs from as far north as the Carolinas, Bermuda and south to Brazil.The Brazilian Seahorse has many colors, and is one of the largest known species.
In the wild, the Dwarf Seahorse (Hippocampus zostera) is found in the western Atlantic Ocean, from Bermuda to the Bahamas, southern Florida and the entire Gulf of Mexico. As the name Dwarf Seahorse implies, this is a tiny species that attains less than two inches in size, which makes them ideal for mini or nano-reef tanks.
The Lined Seahorse (Hippocampus erectus) is also known as the Erect or Atlantic Seahorse. This Seahorse adapts well to aquarium life if it is fed properly and their tank is well maintained. The Lined Seahorse prefers a quiet tank with other non aggressive fish, such as the Mandarin Dragonet.
The Smooth Seahorse (Hippocampus kuda) is also known as the Spotted, Yellow, or Black Seahorse. A protective trait that this and many other seahorses have is the ability to change color to match into their surroundings. It is not unusual for them to take on the coloration of a favorite object one has decided to adopt as a hiding place.