HeadIt sits at a right angle to the body. That gives the seahorse its horse-like look.
SnoutA long tube with a small toothless mouth at its end. It sucks up food.
EyeEach eye can move on its own. One can look ahead while the other looks back.
CoronetA crown-like bump on top of the head. Its shape differs from species to species.
NeckA flexible, bent neck. Most fish have no neck at all.
TrunkThe wide middle part of the body. It runs from the neck down to the tail.
Prehensile tailA tail that can grip. The seahorse winds it round seaweed or coral to stay put.
Dorsal finThe fin on the back. Its rapid motion pushes the seahorse along.
Pectoral finOne small fin on each side, behind the eye. The pair is used for steering.
Bony ringsRings of bony plates under the skin. A seahorse has these in place of scales.
Brood pouchOnly males have one. The female lays her eggs in it and he carries them.
How this list was compiled: Every name checked on 2026-10-01 and kept only where two independent sources use it. (1) Wikipedia, text only: Seahorse, https://en.wikipedia.org/wiki/Seahorse . (2) The Florida Museum of Natural History's species profile of the lined seahorse, https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/hippocampus-erectus/ . (3) The University of Michigan's Animal Diversity Web account of the same species, https://animaldiversity.org/accounts/Hippocampus_erectus/ . Head, eye and pectoral fin rest on sources 1 and 3; snout, neck, trunk and coronet on 1 and 2; dorsal fin, bony rings, brood pouch and prehensile tail are in all three. Licence: own work
The drawing: Drawn for this site on 2026-10-05 by script. The outline of the head, trunk and tail was laid out after a public domain plate: Hugh M. Smith, The Fishes of North Carolina (1907), fig. 67, Sea-Horse, Hippocampus hudsonius (Wikimedia Commons, file FMIB 51397; public domain). Changed from the plate: a slightly longer snout, no skin filaments, a plain low coronet, the armour drawn as lines, and a brood pouch added, since the plate shows a female. Not to scale. Licence: own drawing; outline after a public domain plate
How it works
A seahorse is a fish, but it has no scales and no tail fin, and it swims upright. Start at the head and work down to the curled tail.
Read the full guide
The head is where it looks like a horse
The head bends forward on a neck. A long snout sucks up food, each eye moves on its own, and a small crown called the coronet sits on top.
The body is armor, two fins and a tail
Bony rings cover the trunk in place of scales. The dorsal fin on the back drives the seahorse along, and a small pectoral fin on each side steers. The tail has no fin: it curls and grips. A male also has a brood pouch.
The seahorse drawn is a male. A female has no brood pouch.
No tail fin and no scales: two quick ways to tell a seahorse from other fish.
Questions and answers
What are the parts of a seahorse?
A head with a long snout, two eyes and a coronet on top, a bent neck, a trunk covered in bony rings, a dorsal fin on the back, a pectoral fin on each side and a prehensile tail. Males also have a brood pouch.
What is the crown on a seahorse's head called?
It is called the coronet. It is a crown-like bump or spine on top of the head, and its shape is different for each species of seahorse.
Do seahorses have fins?
Yes. The dorsal fin on the back pushes the seahorse along, and a small pectoral fin on each side of the head steers. A seahorse has no tail fin and no pelvic fins.
What is a seahorse's pouch for?
Only the male has a brood pouch, on the front of the body at the base of the tail. The female lays her eggs in it, and the male carries them until the young are born.