Lined Seahorse

Physical Characteristics

The Lined Seahorse has a slender, elongated body with a horse-like head. Its body is covered in bony plates forming rings, rather than scales. They possess a long, prehensile tail used for gripping onto seagrass or corals. Coloration is highly variable, ranging from black, brown, green, yellow, to orange, often with pale or white lines or spots. Males often develop a prominent brood pouch at the base of the tail during breeding season, as seen in the image. They have a small, tubular snout, and small dorsal and pectoral fins used for propulsion and stability.

Habitat & Distribution

Lined Seahorses are typically found in shallow, temperate to sub-tropical coastal waters, ranging from 0.5 to 70 meters in depth. They inhabit seagrass beds, estuaries, mangroves, coral reefs, and sometimes attach to floating Sargassum seaweed. Their distribution spans the Western Atlantic Ocean, from Nova Scotia in Canada down to the Caribbean Sea and the Gulf of Mexico, and along the coast of South America to Uruguay.

Size & Weight

Adult Lined Seahorses typically reach a length of 12 to 19 cm (5 to 7.5 inches), though some individuals can grow up to 25 cm (10 inches). Weight is generally very light, usually in the range of a few grams, as they are not dense or muscular fish.

Similar Looking Species

Other seahorse species can look similar, such as the Longsnout Seahorse (Hippocampus reidi) which generally has a longer snout and more slender body, or the Dwarf Seahorse (Hippocampus zosterae) which is much smaller. Distinguishing features often include snout length, body markings, and the presence or absence of specific spines or coronet structures on the head.

Ecological Role

Lined Seahorses are ambush predators, feeding primarily on small crustaceans and other invertebrates that drift past. Their cryptic camouflage helps them hide from both predators and prey. They play a role in their ecosystem by controlling populations of their prey. Their conservation status is 'Vulnerable' according to the IUCN Red List, mainly due to habitat degradation (especially seagrass beds) and incidental capture in fishing gear. They are also impacted by the aquarium trade and traditional medicine.

Identified on: 8/14/2025

Mode: Standard