Big blue octopus

About this species

Octopus cyanea, also known as the big blue octopus or day octopus, is an octopus in the family Octopodidae. It occurs in both the Pacific and Indian Oceans, from Hawaii to the eastern coast of Africa. O. cyanea grows to 16 cm in mantle length with arms to at least 80 cm. This octopus was described initially by the British zoologist John Edward Gray in 1849; the type specimen was collected off Australia and is at the Natural History Museum in London.

Text from the Wikipedia article “Octopus cyanea”, licensed CC BY-SA 4.0. Read the article

Where and when

Where it has been recorded

Worldwide

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Best months

Worldwide (open data)

January: 401 records
February: 353 records
March: 388 records
April: 420 records
May: 423 records
June: 393 records
July: 415 records
August: 403 records
September: 497 records
October: 484 records
November: 437 records
December: 386 records

Depth and water temperature

Depth

Mostly recorded at 2–14 m · Deepest record: 82 m

0–10 m: 60 records
10–20 m: 72 records
20–30 m: 3 records
30–40 m: 0 records
40–50 m: 0 records
50–60 m: 0 records
60–70 m: 0 records
70–80 m: 0 records
80–90 m: 1 records

Water temperature

Recorded in surface water of 13–30 °C

12–14 °C: 1 records
14–16 °C: 0 records
16–18 °C: 0 records
18–20 °C: 0 records
20–22 °C: 0 records
22–24 °C: 14 records
24–26 °C: 28 records
26–28 °C: 24 records
28–30 °C: 45 records

Photos

(c) cello caruso-turiello, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Tom Heijnen, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Georgina Jones, some rights reserved (CC BY-SA) · CC BY-SA · iNaturalist
(c) cello caruso-turiello, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Gergely Nigg, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Robin White, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Gergely Nigg, some rights reserved (CC BY) · CC BY · iNaturalist

Names and classification

English: Big blue octopus, Cyane's octopus, Day octopus, big blue octopus, day octopus

Names in 3 more languages

German: Großer Blauer Krake
Japanese: ワモンダコ
Simplified Chinese: Lán-Xiāo, 土婆, 藍章

Other scientific names: Callistoctopus magnocellatus, Octopus glaber, Octopus herdmani, Octopus horsti, Octopus marmoratus, Sepia barffi

Similar species

Algae Octopus
Abdopus aculeatus
Greater blue-ringed octopus
Hapalochlaena lunulata
Mimic octopus
Thaumoctopus mimicus
Wonderpus
Wunderpus photogenicus
Mosaic Drop-arm Octopus
Abdopus abaculus

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).
1,277 open-data records from 1849 to 2023.
Species data updated October 26, 2026.