Black surgeonfish
Acanthurus gahhm
- Usual depth0–7 m
- Water temperature25–30 °C
- Best monthsFebruary, July, and August
- How commonRare
Photo credit: (c) Derek Keats, some rights reserved (CC BY) · CC BY · iNaturalist
About this species
Acanthurus gahhm, the black surgeonfish, monk surgeonfish or lined surgeonfish, is a species of marine ray-finned fish belonging to the family Acanthuridae, the surgeonfishes, unicornfishes or tangs. This fish is found in the western Indian Ocean.
Text from the Wikipedia article “Acanthurus gahhm”, 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: 9 records
- February: 36 records
- March: 14 records
- April: 11 records
- May: 8 records
- June: 10 records
- July: 30 records
- August: 26 records
- September: 22 records
- October: 26 records
- November: 18 records
- December: 15 records
Depth and water temperature
Depth
Mostly recorded at 0–7 m · Deepest record: 18 m
Water temperature
Recorded in surface water of 25–30 °C
Photos
(c) Dr. Guido Bohne, some rights reserved (CC BY-SA), uploaded by Dr. Guido Bohne · CC BY-SA · iNaturalist 
no rights reserved, uploaded by Jean-Paul Boerekamps · CC0 1.0 · iNaturalist 
(c) Jan Ebr & Ivana Ebrová, some rights reserved (CC BY) · CC BY · iNaturalist 
(c) Jan Ebr & Ivana Ebrová, some rights reserved (CC BY) · CC BY · iNaturalist 
(c) Ульяна Лалак, some rights reserved (CC BY) · CC BY · iNaturalist 
(c) Jonathan Maitrot, some rights reserved (CC BY) · CC BY · iNaturalist 
no rights reserved · CC0 1.0 · iNaturalist
Names and classification
- English
- Black surgeonfish, dusky surgeonfish
Other scientific names: Acanthurus gahm
Similar species
Eyestripe surgeonfishAcanthurus dussumieri
Lined surgeonfishAcanthurus lineatus
BacksurgeonfishAcanthurus nigricans
Brown surgeonfishAcanthurus nigrofuscus
Bluelined surgeonfishAcanthurus nigroris
Gendarme FishAcanthurus olivaceus
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).
- 193 open-data records from 1775 to 2015.
- Species data updated October 26, 2026.
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