Fish

Threadfin Mirrorfish

Alectis ciliaris

A tall, mirror-silver jack whose young trail long thread-like fin filaments - a prized spearfishing target that grows to a metre and a half.

Also known as draadvin- spieelvis

Threadfin Mirrorfish
Photo: Mark Rosenstein · CC BY-NC 4.0
Typical size
Attains 150 cm
Habitat
Coastal waters and reefs; adults shoal

The threadfin mirrorfish is a deep, laterally flattened jack, mostly silvery with a dusky green sheen on the back and a small, faint spot on the gill cover. Young and juveniles trail extremely long, filamentous dorsal and anal rays and carry five to seven broad dark bands; the skin looks smooth, its scales minute and embedded. It reaches 150 cm, with a South African spearfishing record of 21.4 kg.

Adults gather in large shoals and are common in coastal waters, including reef areas, while the trailing-finned juveniles are solitary and often move into sheltered water.