Longbarb dragonfish

Flagellostomias boureei

Fish
IUCN: Least concern

Usual depth151–1,300 m
Water temperature9–30 °C
Best monthsJune
How commonRare

About this species

Flagellostomias boureei, the Longbarb dragonfish, is a species of barbeled dragonfish found in the ocean depths worldwide. This species grows to a length of 32.2 centimetres (12.7 in) SL. This species is the only known species in its genus.

Text from the Wikipedia article “Flagellostomias”, 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: 1 records
February: 9 records
March: 3 records
April: 5 records
May: 10 records
June: 31 records
July: 15 records
August: 6 records
September: 7 records
October: 7 records
November: 7 records
December: 5 records

Depth and water temperature

Depth

Mostly recorded at 151–1,300 m · Deepest record: 2,280.5 m

50–60 m: 1 records
60–70 m: 0 records
70–80 m: 2 records
80–90 m: 0 records
90–100 m: 1 records
100–110 m: 2 records
110–120 m: 2 records
120–130 m: 0 records
130–140 m: 1 records
140–150 m: 0 records
150–160 m: 2 records
160+ m: 92 records

Water temperature

Recorded in surface water of 9–30 °C

8–10 °C: 7 records
10–12 °C: 13 records
12–14 °C: 17 records
14–16 °C: 10 records
16–18 °C: 11 records
18–20 °C: 6 records
20–22 °C: 14 records
22–24 °C: 20 records
24–26 °C: 2 records
26–28 °C: 10 records
28–30 °C: 6 records

Names and classification

English: Longbarb dragonfish, Scaleless dragonfish, Black Dragonfish, Longbarb Dragonfish

Names in 3 more languages

Spanish: dragón de barba larga
French: Idiacanthe Ruban
Japanese: Muchihoshieso, ムチホシエソ

Other scientific names: Aristostomias uncodentatus, Eustomias boureei, Flagellostomias bourei, Flagellostomias tyrannus

Similar species

Manylight fangfish
Chauliodus sloani
Pacific viperfish
Chauliodus macouni
Straightline dragonfish
Borostomias antarcticus
Pacific blackdragon
Idiacanthus antrostomus
Scaleless dragonfish
Echiostoma barbatum
Black dragonfish
Idiacanthus atlanticus

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).
292 open-data records from 1912 to 2021.
Species data updated November 2, 2026.

Log what you see on your next dive

The free DiveHive diver app keeps your logbook with every sighting and shows what lives at the site you dive next.

Join the waitlist