Western Spiny Seahorse
Hippocampus angustus
- Least concern
- Card rarity: Common
- Fish

Hippocampus angustus, commonly known as the narrow-bellied seahorse, western Australian seahorse, or western spiny seahorse, is a species of marine fish of the family Syngnathidae. It is found in waters off of Australia, from Perth to Hervey Bay, and the southern portion of Papua New Guinea in the Torres Strait. It lives over soft-bottom substrates, adjacent to coral reefs, and on soft corals at depths of 3–63 metres (9.8–206.7 ft). It is expected to feed on small crustaceans, similar to other seahorses. This species is ovoviviparous, with males carrying eggs in a brood pouch before giving birth to live young. This type of seahorse is monogamous in its mating patterns. The males only fertilize one female's eggs for the mating season because of the population distribution.
Classification
- Class
- Actinopterygii
- Order
- Syngnathiformes
- Family
- Syngnathidae
- Genus
- Hippocampus