Seahorses are mainly found in shallow tropical and temperate salt water throughout the world, from about 45°S to 45°N.[8] They live in sheltered areas such as seagrass beds, estuaries, coral reefs, and mangroves. Four species are found in Pacific waters from North America to South America. In the Atlantic, Hippocampus erectus ranges from Nova Scotia to Uruguay. H. zosterae, known as the dwarf seahorse, is found in the Bahamas.
Colonies have been found in European waters such as the Thames Estuary.[9]
Two species live in the Mediterranean Sea: H. guttulatus (the long-snouted seahorse), H. hippocampus (the short-snouted seahorse).[10][11] These species form territories; males stay within 1 m2 (10 sq ft) of habitat, while females range over about one hundred times that.[12]