All fish / Syngnathidae

Thorny Seahorse

Hippocampus histrix

Also known as spiny seahorse, thorny sea horse, spiny sea horse, histrix seahorse, prickly seahorse, ม้าน้ำหนาม, kuda laut berduri, イバラタツ, kuda laut duri, 刺海马

A slender seahorse with a long snout and long, sharp spines over the head and body, usually yellow, orange, red or brown. Keepers value it for its striking spiny outline and calm, deliberate behaviour in a quiet species tank.

Care at a glance

Care level

Hard

Temperament

Peaceful

Adult size

15 cm

Temperature

22 to 26 °C

pH

8.1 to 8.4

Smallest tank

190 litres

Keep as

A pair or small group of its own kind

Diet

Carnivore: frozen enriched mysis shrimp, live brine shrimp and small crustaceans, fed several times a day

Swims

Middle of the tank

Lifespan

3 to 5 years

Water

Marine (saltwater)

Wild range

Indo-Pacific: East Africa and Red Sea to Japan, Indonesia, Philippines and northern Australia

Breeding

The male carries the eggs in a brood pouch and releases fully formed young after a few weeks. Captive breeding happens but rearing the tiny fry on live foods such as copepods and rotifers is demanding.

Good to know

All Hippocampus species are listed on CITES Appendix II, so buy captive bred stock where possible. Keep only with gentle tankmates and slow flow, as fast or nippy fish will outcompete it for food.