Description:

Dorsal spines: 7; Dorsal rays: 9; Anal spines: 2; Anal rays: 8.

Small cardinal fish with moderately elongate body. Whitish base colour with 5-6 dark stripes, midlateral stripe ending in a distinct black spot at caudal fin base.
 

Maturity: Lm unknown. Range unknown. Max Length: 10cm.

Occurs inshore in shallow, protected waters )depth 1-10m, but generally in less than 2m) Found close to ledges of rocky areas or coral reefs during the day. 
Nocturnal species. Solitary or in small groups. Distinct pairing during courtship and spawning. Mouthbrooders.
 

This species is not protected or subject to fishery regulations. It is not caught in artisanal fishery.

Allen, G. et al (2015). Ostorhinchus cookii. The IUCN Red List 2015: https://www.iucnredlist.org/species/193299/56994054. (31/10/21).
Froese, R. & D. Pauly. Eds. (2021). FishBase. Ostorhinchus cookii https://www.fishbase.se/summary/9240 (31/10/21).
 

Nevill, J.E.G. (2019). Ostorhinchus cookii, Cook's cardinalfish. Seychelles Seatizens. www.seatizens.sc. https://seatizens.sc/species/ostorhinchus-cookii-macleay-1881/ (Updated 31/10/21).