Atoll Butterflyfish
Chaetodon mertensii
- Usual depth5–22 m
- Water temperature20–29 °C
- Best monthsJuly, September, and October
- How commonOccasional
Photo credit: (c) Susan Prior, some rights reserved (CC BY) · CC BY · iNaturalist
About this species
Chaetodon mertensii, the atoll butterflyfish, yellowback butterflyfish or Merten's butterflyfish, is a species of marine ray finned fish, a butterflyfish belonging to the family Chaetodontidae. It is found in the western Pacific Ocean.
Text from the Wikipedia article “Chaetodon mertensii”, licensed CC BY-SA 4.0. Read the article
Where and when
Where it has been recorded
Worldwide
Loading the map
Best months
Worldwide (open data)
- January: 29 records
- February: 64 records
- March: 87 records
- April: 118 records
- May: 127 records
- June: 169 records
- July: 211 records
- August: 109 records
- September: 234 records
- October: 171 records
- November: 79 records
- December: 39 records
Depth and water temperature
Depth
Mostly recorded at 5–22 m · Deepest record: 41 m
Water temperature
Recorded in surface water of 20–29 °C
Photos
(c) natomik, some rights reserved (CC BY) · CC BY · iNaturalist 
(c) Susan Prior, some rights reserved (CC BY) · CC BY · iNaturalist 
(c) Debra Baker, some rights reserved (CC BY) · CC BY · iNaturalist 
(c) João D'Andretta, some rights reserved (CC BY) · CC BY · iNaturalist 
(c) Debra Baker, some rights reserved (CC BY) · CC BY · iNaturalist 
(c) Valentin Moser, some rights reserved (CC BY) · CC BY · iNaturalist 
(c) jeyre, some rights reserved (CC BY) · CC BY · iNaturalist
Names and classification
- English
- Atoll Butterflyfish, Merten's Butterflyfish, Merten's Coralfish, Orangebar Butterflyfish
Names in 2 more languages
- French
- Chaetodon de Mertens
- Japanese
- Beniochochouo, Benio-chôchô-uo, ベニオチョウチョウウオ
Other scientific names: Chaetodon dixoni, Chaetodon mertensi
Similar species
Threadfin butterflyfishChaetodon auriga
Citron ButterflyChaetodon citrinellus
Blackblotch ButterflyfishChaetodon ephippium
Sunburst butterflyfishChaetodon kleinii
Raccoon butterflyfishChaetodon lunula
Oval ButterflyfishChaetodon lunulatus
Sources and credits
Names and taxonomy: WoRMS (CC BY 4.0) and the GBIF Backbone (CC BY 4.0). Photos: iNaturalist observers, each under the licence shown (CC0, CC BY or CC BY-SA).
- Depth, temperature, months and maps: records from OBIS and GBIF under CC0 or CC BY.
- Descriptions: Wikipedia, licensed CC BY-SA, each linked to its article.
- Conservation status as published by GBIF (IUCN Red List).
- 1,927 open-data records from 1902 to 2023.
- Species data updated October 26, 2026.
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