Denver Zoo Map

Hippocampus erectus



Class: Osteichthyes
Order: Syngnathiformes
Family: Syngnathidae
Genus: Hippocampus
Species: erectus

Fun Facts

  • Seahorses are one of the most unusual of all fish. Their upright position, horse-like head and jointed bony plates resemble the knight in a chess set.
  • Seahorses are true bony fish complete with gills, fins and a swim bladder.
  • The male seahorse becomes pregnant, incubates the fertilized eggs and gives live birth.
  • Seahorses are difficult to keep as aquarium fish because they require live food and they are vulnerable to a range of bacterial, fungal and parasitic diseases.
  • The work “hippocampus” comes from the Greek words “hippo” meaning horse and “campus” meaning sea monster. They are named for the mythical half horse, half fish creature in Greek mythology.



Ocean seahorses occur from the southern tip of Nova Scotia in Canada, along the east coast of the U.S. south to Brazil and into the Gulf of Mexico.


The seahorse is found in marine habitats associated with aquatic vegetation such as seagrass, eelgrass, mangroves and sponges.

Physical Description

  • The oceanic seahorse is up to five inches (12.7 cm) long.
  • They are brownish yellow with a characteristic pattern of white lines down the neck and tiny white dots on the tail.
  • They have a horse-like head, a prehensile tail and a long tubular snout.
  • Their body is covered with bony plates rather than scales like other fish.
  • Their eyes can move independently or converge to allow binocular vision.


What Does It Eat?

In the wild: Small fish fry, crustaceans, other invertebrates – basically any live animals small enough to fit in their mouth. 
At the zoo: Mysis shrimp and hatch brine shrimp to the youngest.

What Eats It?

Crabs and large fish prey on seahorses.

Social Organization

Seahorses are not social fish except for monogamous mated pairs.

Life Cycle

Seahorses are monogamous mating exclusively with the same partner during their lifetime. During courtship, the male and female intertwine their tails to allow the female to position herself over the male’s brood pouch. The female deposits long sticky strings of eggs (250-650 eggs) into the pouch. The eggs are fertilized by sperm inside the male’s pouch and the resulting embryos develop for 20-21 days. The male gives birth holding fast to a plant stem while ejecting the fully independent young who receive no further care or assistance from either parent. The young are less than and inch long at birth – miniature copies of the adult seahorse. Daily greeting rituals reinforce the bond between a monogamous pair of seahorses even during the pregnancy. These greeting rituals facilitate reproductive synchrony so the female has ripe eggs ready as soon as the male gives birth. The pair mates soon after the birth and begin the cycle again. Seahorses mature at eight to 10 months, and can live four to five years.


Not So Speedy

Seahorses are better at maneuverability than speed. Only the little dorsal fin on their back provides propulsion. The pectoral fins below the gill opening are used for stability and steering. The muscular tail is used as an anchor to keep the seahorse from drifting away.

Can You See Me Now?

Seahorses are masters of camouflage with blotchy skin patterns that help break up their outline. They can also change color to match their surroundings. Their skin is often covered with organisms such as algae that provide further camouflage and protection from predators. Seahorses are not fast at changing color, requiring a few minutes to change color.

Click, Click, Hello

Seahorses can make noises, mainly small clicks produced by moving two parts of their skull against each other. The sounds have sexual significance and are often produced by mating pairs.

Conservation Connection

IUCN Status – Vulnerable.
Seahorses are listed as vulnerable because of habitat loss and because they are exploited for traditional Chinese medicines, the aquarium trade and as tourist curios. They are captured and dried for traditional Chinese medicines used to treat a variety of ailments from asthma to infertility to heart disease. They are desirable as tourist curios because they retain their extraordinary shape after they are dried so they can be made into jewelry, paperweights and other curios. Almost all seahorses for the aquarium trade are wild caught because they are difficult to breed in captivity.

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