Marine life  /  Seahorses & pipefish  /  Satomi's pygmy seahorse
Reviewed 2026-09-06
Species entry

Satomi's pygmy seahorse

Hippocampus satomiae

The smallest seahorse described, at 14 mm, on gorgonians and soft corals on steep slopes.

Size
To 14 mm
Depth
8–25 m
Habitat
Gorgonians and soft corals on slopes
Active
Day and night
Range
Indo-Pacific
Rarity
Lembeh Strait
5 stars of 5, a handful of records
SP-01
satomi's pygmy seahorse · full body · habitat
4:3 · min 2400px

About 11 to 14 mm, which makes it the smallest seahorse yet described and smaller than either of the free-living pygmies it is confused with. Twelve trunk rings and 30 to 31 tail rings, a raised and flanged coronet, and a body carrying short spines and a few fleshy filaments rather than the bulbous tubercles of Bargibant’s. The animals it is mistaken for are Pontoh’s and Walea’s: Pontoh’s has a pair of wing-like spines on each of the first two superior trunk ridges and 28 to 30 tail rings, and Walea’s is deeper-bodied with 32 tail rings and a low coronet of two rounded mounds. At this size none of that is countable in the water, and an honest identification usually waits for the photograph.

Unlike Bargibant’s and Denise’s it is not confined to gorgonians. Records place it on gorgonians, on soft corals and on hydroids, generally on steep slopes and wall faces between about 8 and 25 m, and often on the shaded underside of a branch rather than the open face. It is reported to be more active after dark. The species was described in 2008 from material collected off Kalimantan, and the diver record since has been patchy and comes mostly from Indonesian slopes, so a destination missing from the list here means the records are thin rather than that the animal is absent. Males brood in a closed pouch at the front of the tail, as all seahorses do, and at this size a brooding male shows only a slight swelling.

A pygmy that will not leave its branch cannot move away from a strobe, and repeated flash on the same animal through a day of dive boats is a cost the seahorse carries rather than the photographer.

Where to find:

LocationRarity Best monthsDepthHabitat
Lembeh Strait Indonesia editorial estimate
5 stars of 5, a handful of records
Year-round
8–25 m
Gorgonians and soft corals on slopes
Ambon Indonesia editorial estimate
5 stars of 5, a handful of records
Year-round
10–25 m
Gorgonians and soft corals
Bali Indonesia editorial estimate
5 stars of 5, a handful of records
Year-round
10–25 m
Gorgonians and soft corals

Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.

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