Blackthroat Threefin
Helcogramma decurrens
Blackthroat Threefin (Helcogramma decurrens) is a small reef-associated triplefin reported from tropical Indo-Pacific locality records. It inhabits shallow coastal hard-bottom areas where it stays close to rock and coral surfaces and feeds on tiny drifting and benthic invertebrates.
Identification points
- Very small triplefin with three separate dorsal fins
- Dark blackish throat or lower head area contrasted with a paler body
- Slender reef-dwelling body with a blunt head and large eyes
Habitat
Shallow tropical coastal reefs, rubble, and rocky surge zones; usually among coral heads, crevices, and algal-encrusted hard substrate in very shallow water.
Bait notes
Not a standard game fish and usually too small for targeted angling. If collected for study or aquarium use where legal, tiny planktonic foods, mysid shrimp, copepods, or micro-jigs would match its prey size; standard bait is ineffective.
Behavior
A small benthic ambush feeder that perches low on the substrate and picks at minute crustaceans and other zooplankton/invertebrates. It is cryptic, quick to dart into cover, and is typically seen singly or in loose small groups.
Caution
Handle gently because of its very small size and reef habitat; avoid trampling shallow coral and rocky habitat. Follow local marine collection and protected-area regulations, which may restrict take in reef zones.
Fishing notes
Not commonly fished; best encountered by sight in shallow reef tide pools, surge channels, or snorkel surveys rather than by rod and reel. Fine-mesh hand nets or specialized collection methods are more relevant than conventional tackle, and local collection rules may prohibit capture.