Yellowback fusilier (Caesio xanthonota)

Classification (WoRMS)

Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Chordata · Class: Teleostei · Order: Eupercaria incertae sedis · Family: Caesionidae · Genus: Caesio.

Accepted name: Caesio xanthonota · Authority: Bleeker, 1853 · Taxonomic status: accepted · AphiaID: 219994.

Synonyms and superseded combinations recorded for this taxon: Caesio xanthonatus Bleeker, 1853; Caesio xanthonotus Bleeker, 1853.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=219994 (CC BY 4.0). Accessed 2026-09-25.

Biology and life history (FishBase)

Measured values published by FishBase for Caesio xanthonota. Only fields the database actually holds for this species are shown; these are database values, not aquarium guidance.

Maximum length: 40 cm · Depth range: 0–50 m · Habitat zone: reef-associated · Body shape: fusiform / normal · Vulnerability index: 30 of 100 · Fishery importance: minor commercial · Aquarium trade: never/rarely.

FishBase notes: Inhabits deep lagoons and along seaward reefs (Ref. 9710), primarily around coral reefs. Feeds on zooplankton in large midwater aggregations. Oviparous, with numerous, small pelagic eggs (Ref. 402).

Source: FishBase species summary (SpecCode 927) — https://www.fishbase.se/summary/Caesio-xanthonota.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-25.

Distribution and occurrence records (GBIF)

589 georeferenced occurrence records for Caesio xanthonota are published through GBIF from 32 countries or marine areas. The map above plots 115 distinct locations from a sample of 589 records, omitting 11 inland records that carry an institution's coordinates rather than a collection site; it shows where the species has been observed and reported, not a modelled range.

Most records by country or area: Mayotte (195); Maldives (80); Seychelles (47); South Africa (40); Thailand (33); Madagascar (30); Mozambique (30); Indonesia (29); Kenya (19); India (11); Philippines (9); Réunion (8); French Southern Territories (8); Egypt (7); Tanzania, United Republic of (7).

Marine regions with a valid WoRMS distribution record: Kenyan Exclusive Economic Zone; Tanzanian Exclusive Economic Zone; Somali Exclusive Economic Zone; Seychellois Exclusive Economic Zone; Madagascar; Comoran Exclusive Economic Zone; Chagos; Réunion Exclusive Economic Zone; South Africa (country); Mozambican Exclusive Economic Zone.

Source: GBIF Occurrence Search (taxonKey 2374795) — https://www.gbif.org/occurrence/search?taxon_key=2374795&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=219994 (CC BY 4.0); Natural Earth 110m basemap — https://www.naturalearthdata.com/ (public domain). Accessed 2026-09-25.

Conservation status (IUCN Red List)

The IUCN Red List assesses Caesio xanthonota Bleeker, 1853 as Least Concern (code LC). No trend, population estimate or threat analysis is given here, because none is available from this source without the Red List API; follow the source link for the full assessment, including its date.

Source: IUCN Red List of Threatened Species (taxon 20250214) — https://www.iucnredlist.org/species/20250214/0; GBIF IUCN Red List category endpoint (taxonKey 2374795) — https://api.gbif.org/v1/species/2374795/iucnRedListCategory. Accessed 2026-09-25.

Description and natural history (Wikipedia)

The yellowback fusilier was first formally described in 1853 by the Dutch ichthyologist Pieter Bleeker with the type locality given as Batavia on Java. This species has been placed in the subgenus Flavicaesio. The specific name xanthonota is a compunction of xantho meaning "yellow" and nota meaning "back", a reference to the yellow upperparts of this species.

The yellowback fusilier is a small to medium-sized fish which grows to about 40 cm long. The mouth is small and terminal and is protusible, being able to be extended forward to swallow food. The body is fusiform or spindle-shaped.

The dorsal fin has 10 spines and 14–15 soft rays. The anal fin has three spines and 11 or 12 soft rays. The caudal fin is deeply forked.

The body coloration is greyish blue with a bright yellow zone on the back. The yellow area goes from the forehead, between the eyes, to the tail, and includes the dorsal fin and the caudal fin. This area corresponds more or less to the upper third of the body. The belly is plain white.

Caesio xanthonota is widely distributed throughout the tropical waters of the Indian Ocean, the Red Sea and Persian Gulf excluded, to Indonesia in the western Pacific Ocean. It lives in mid-water in deep lagoons and close to external reefs from the surfaceto 50 m deep.

It feeds on zooplankton, so it is a planktivore.

The yellowback fusilier is diurnal, and lives in groups and forms schools with other caesionids such as Caesio teres.

Source: Wikipedia: Yellowback fusilier — https://en.wikipedia.org/wiki/Yellowback_fusilier (CC BY-SA 4.0). Accessed 2026-09-25.