Oval butterflyfish (Chaetodon lunulatus)

Classification (WoRMS)

Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Chordata · Class: Teleostei · Order: Acanthuriformes · Family: Chaetodontidae · Genus: Chaetodon.

Accepted name: Chaetodon lunulatus · Authority: Quoy & Gaimard, 1825 · Taxonomic status: accepted · AphiaID: 398549.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=398549 (CC BY 4.0). Accessed 2026-09-23.

Biology and life history (FishBase)

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

Maximum length: 26.700000762939453 cm · Depth range: 0–60 m · Habitat zone: reef-associated · Body shape: short and / or deep · Vulnerability index: 16.7 of 100 · Aquarium trade: never/rarely.

FishBase notes: Occur in monogamous pairs in coastal coral-rich areas (Ref. 47838, 48636). Juveniles hide among branches of small corals, often in lagoons (Ref. 9407). Benthopelagic (Ref. 58302). Feed solely on live corals (Ref. 47838). Oviparous (Ref. 205). Form pairs during breeding (Ref. 205).

Source: FishBase species summary (SpecCode 14300) — https://www.fishbase.se/summary/Chaetodon-lunulatus.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.

Distribution and occurrence records (GBIF)

11,243 georeferenced occurrence records for Chaetodon lunulatus are published through GBIF from 39 countries or marine areas. The map above plots 308 distinct locations from a sample of 3,000 records, omitting 38 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: Australia (2,561); French Polynesia (1,284); New Caledonia (922); United States of America (893); Tonga (781).

The full country table, WoRMS marine regions and the sampling notes are on this species' Distribution page.

Source: GBIF Occurrence Search (taxonKey 2385403) — https://www.gbif.org/occurrence/search?taxon_key=2385403&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=398549 (CC BY 4.0); Natural Earth 110m basemap — https://www.naturalearthdata.com/ (public domain). Accessed 2026-09-23.

Conservation status (IUCN Red List)

The IUCN Red List assesses Chaetodon lunulatus Quoy & Gaimard, 1825 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 165704) — https://www.iucnredlist.org/species/165704/0; GBIF IUCN Red List category endpoint (taxonKey 2385403) — https://api.gbif.org/v1/species/2385403/iucnRedListCategory. Accessed 2026-09-23.

Description and natural history (Wikipedia)

The blacktail butterflyfish (C. austriacus), melon butterflyfish (C. trifasciatus), and oval butterflyfish (C. lunulatus) are similar in coloration. The former has black caudal and anal fins, while the latter is an Indian Ocean species and has a more conspicuous back patch below the dorsal fin and a mainly yellow anal fin. Chaetodon lunulatus can grow up to 14 cm long. It has about 13-14 dorsal spines, 20-22 dorsal soft rays, three anal spines, and 18-21 anal soft rays.

Together with the black-tailed and melon butterflyfishes, and probably also the somewhat aberrant Arabian butterflyfish (C. melapterus), it makes up the subgenus Corallochaetodon. They are probably quite close to the subgenus "Citharoedus" (the name is a junior homonym of a mollusc genus), which contains the scrawled butterflyfish (C. meyeri). Like that group, they might be separated in Megaprotodon if the genus Chaetodon is split up.

Oval butterflyfish can be found in the Pacific Ocean from Japan and Australia to the North and South and Hawaii and the Tuamotu Islands to the East. They are benthopelagic and can be found in coral reefs in the tropics. They can be found at a depth of 3 to 30 meters in coral-rich lagoons and semi-protected seaward reefs. Small juveniles are secretive and hide in corals.

The butterflyfish species feeds almost exclusively on hard corals. The oval butterflyfish is a widespread corallivore and has been found to feed on 51 different types of coral, including Acropora florida, A. gemmifera, A. hyacinthus, A. intermedia, and Pocillopora damicornis.

Coral bleaching has been shown to affect Chaetodon lunulatus. A 2004 study found a noticeable decline in the physiological condition of the oval butterflyfish before and immediately after a coral bleaching event, possibly leading to reductions in survivorship. A 2006 study found a significant decline in the abundance of various species of butterflyfish (including C. lunulatus) after a bleaching event in the Great Barrier Reef. Only obligate coral-feeding butterflyfishes, such as C. lunulatus, and not facultative or non-coral feeders displayed reductions in abundance. It has been suggested that these declines were due to starvation and death resulting from a lack of coral prey.

The oval butterflyfish is oviparous and has little sexual dimorphism. In C. lunulatus, both solitary living and pair bonding occurs amongst individuals. Studies have found that heterosexual pairing predominates, most likely to facilitate reproduction. Partner fidelity appears long-lasting, with one study reporting that individuals remained paired for up to seven years. In these pair-bonds, females feed more frequently, while males tend to take the leading position when swimming in tandem. The pairs display a high level of parallel and proximate (1.5m) swimming, and almost always remain in close range (4m).

Butterflyfish defend their territories against conspecifics. A tail-up display is a common antagonistic behavior in the Chaetodon species. It is performed towards conspecifics in territorial disputes as well as in non-agonistic interactions with a pair partner. C. lunulatus may attack individuals when they do not perform the tail-up display. In territorial interactions, the fish display behavioral patterns such as encircling, staring, tail-up display, two-piled-tops fighting, parallel swimming, chasing, rushing, fleeing, and attacking. Fatal fighting only occurs over mating resources but not for resources such as shelter or food.

Source: Wikipedia: Oval butterflyfish — https://en.wikipedia.org/wiki/Oval_butterflyfish (CC BY-SA 4.0). Accessed 2026-09-23.