Hippocampus haema, the Korean seahorse, is a seahorse of the family Syngnathidae native to the northern Pacific Ocean (Korea Strait, Sea of Japan, northeastern coast of Honshu), and it usually lives in Sargassum and weeds on shallow soft bottom habitats from 0 to 18 m depth.

The Japanese name 'Himetatsu' is derived from its smaller shape such as body and coronet rather than the shape of a sister species, crowned seahorse (Hippocampus coronatus).

However, the two genuine species do not live in Korean waters, therefore this species was handled by naming a new scientific name, Hippocampus haema.

[2][7][8][9] However, sex determination of this species is considered as ca.

Breeding season of this species is from April to October or May to November (7 months), relating to warm water temperature.