Home · Polynemidae · Smallmouth threadfin
Smallmouth threadfin (Polydactylus microstomus) — Polynemidae

Smallmouth threadfin

Polydactylus microstomus
Family: Polynemidae

The Smallmouth threadfin (Polydactylus microstomus) is a brackish-water fish of the family Polynemidae that grows up to 25 cm.

Length
25 cm
Water
Brackish
Diet
Carnivore
Behaviour
Small groups
Substrate
Sand / mud bottom
Danger
Harmless
Edibility
Commonly eaten

Description

The smallmouth threadfin is a threadfin (Polynemidae) from the Indo-West Pacific. The species has an elongate, silvery body with a projecting snout and a small, inferior mouth. Below the pectoral fin it bears free, thread-like fin rays that serve as feelers to detect prey on the bottom in turbid water. It inhabits coastal waters and estuaries over soft bottoms. It feeds on small crustaceans, worms and small fishes. The species is harmless to humans.

Frequently asked questions

How do you recognise the Smallmouth threadfin?

The Smallmouth threadfin is mainly silver-grey and shows a plain pattern.

Where does the Smallmouth threadfin live?

The Smallmouth threadfin lives in brackish water and is mostly found around sand or mud bottom.

How big does the Smallmouth threadfin get?

The Smallmouth threadfin grows to a maximum of about 25 cm. On average the species is around 15 cm.

Is the Smallmouth threadfin dangerous to humans?

No, the Smallmouth threadfin is harmless to humans.

Is the Smallmouth threadfin edible?

Yes, the Smallmouth threadfin is commonly eaten.

Download Fin's Fish Guide

Identify fish in seconds, log your catches and dives. Join the TestFlight beta.

Get the beta →

All data

Identification

Dutch name
Kleinbek-draadvinvis sourced
English name
Smallmouth threadfin sourced
Scientific name
Polydactylus microstomus
Family
Polynemidae

Appearance

Max length (cm)
25.0 verified
Average length (cm)
15.0 sourced
Dominant colour
Silver / grey inferred
Pattern
Plain inferred
Tail shape
Forked inferred
Mouth position
Inferior (downward) inferred
Lips
Thick / fleshy inferred
Barbels
No sourced
Dorsal fins
Two separate inferred
Dorsal spines
Yes sourced

Habitat & distribution

Water type
Brackish sourced
Substrate
Sand / mud bottom sourced
Origin
Native sourced

Behaviour & biology

Diet
Carnivore sourced
Social behaviour
Small groups inferred
Territorial
No inferred
Reproduction
Separate sexes sourced
Sexual dimorphism
No inferred

For anglers

Edibility
Commonly eaten sourced
Regulations source
FishBase ↗ inferred

Safety

Danger to humans
Harmless sourced

Status & sources

Sources
FishBase via GBIF (DwC-A), CC-BY-NC 4.0

Same genus Polydactylus

More from the family Polynemidae

Download Fin's Fish Guide

Identify fish in seconds, log your catches and dives. Join the TestFlight beta.

Get the beta →