Green Barrel Sea Squirt

About this species

Didemnum molle is a species of colonial tunicate in the family Didemnidae. It is commonly known as the tall urn ascidian, the green barrel sea squirt or the green reef sea-squirt. It is native to the Red Sea and the tropical waters of the Indo-Pacific region.

Text from the Wikipedia article “Didemnum molle”, 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: 119 records
February: 104 records
March: 141 records
April: 138 records
May: 167 records
June: 112 records
July: 120 records
August: 150 records
September: 326 records
October: 205 records
November: 172 records
December: 99 records

Depth and water temperature

Depth

Mostly recorded at 10–20 m · Deepest record: 146 m

0–10 m: 11 records
10–20 m: 175 records
20–30 m: 28 records
30–40 m: 3 records
40–50 m: 1 records
50–60 m: 0 records
60–70 m: 0 records
70–80 m: 0 records
80–90 m: 0 records
90–100 m: 0 records
100–110 m: 0 records
110+ m: 1 records

Water temperature

Recorded in surface water of 24–30 °C

24–26 °C: 4 records
26–28 °C: 1 records
28–30 °C: 125 records

Photos

(c) portioid, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Donald Davesne, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Donald Davesne, some rights reserved (CC BY) · CC BY · iNaturalist
(c) portioid, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Luke Lythgoe, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Wolfgang Ahlmer, some rights reserved (CC BY) · CC BY · iNaturalist
(c) 呂一起(Lyu yi-chi), some rights reserved (CC BY) · CC BY · iNaturalist

Names and classification

English: Green Barrel Sea Squirt, Green Reef Sea Squirt, Green Urn Ascidian, Urn Ascidian, Urn Sea Squirt, Urn Tunicate

Names in 5 more languages

German: Grüne Riffseescheide
French: Grande synascidie-urne
Japanese: チャツボボヤ
Thai: เพรียงหัวหอมเขียว
Simplified Chinese: 壺海鞘, 柔軟二段海鞘, 柔軟壺海鞘

Other scientific names: Didemnum sycon, Diplosomoides molle, Leptoclinum molle, Lissoclinum molle

Similar species

Moseley's Ascidian
Didemnum moseleyi
Colonial tunicate
Didemnum perlucidum
White crust
Didemnum candidum
Didemnum grande
Didemnum parau
Gray encrusting compound tunicate
Diplosoma listerianum

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).
498 open-data records from 1908 to 2015.
Species data updated October 26, 2026.