threadfish

fish

Also known as: African pompano, Alectis crinitis

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July 14, 2026

Quick Summary

The term "threadfin" or "threadfish" can refer to two distinct types of fish, both characterized by long, filamentous fin rays.

The primary definition refers to marine fish of the family Polynemidae. These fish are found along warm seashores and typically have silvery bodies, two dorsal fins, and a forked tail. Their most distinctive feature is their pectoral fins, which are divided into a standard upper fin and a lower section with several long, threadlike rays. These rays act as sensory organs, particularly in younger fish. While most threadfins are between 30–60 cm (1–2 feet) long, one species can reach up to 1.8 meters (6 feet).1

The term can also apply to fish of the genus Alectis (family Carangidae). These fish also possess long, filamentous fin rays, but these are on their dorsal and anal fins, not their pectoral fins. These rays are more prominent in the young.12

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pompano
The African pompano, or threadfish, also of the family Carangidae, is Alectis crinitis of the Atlantic and eastern Pacific oceans. It is about 90 cm long and, especially when young, has very long, threadlike rays extending from the dorsal and anal fins.
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The African pompano, or threadfish, also of the family Carangidae, is Alectis crinitis of the Atlantic and eastern Pacific oceans. It is about 90 cm long and, especially when young, has very long, threadlike rays extending from the dorsal and anal fins.
Read More