Pygmy leatherjacket
Amazing fact
When courting, male pygmy leatherjackets extend their bellies into a thin flap that turns blue.
市立しものせき水族館 海響館
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An illustration based on the real animal.
A little discovery to share.
When courting, male pygmy leatherjackets extend their bellies into a thin flap that turns blue.
THE REAL WORLD
The real Pygmy leatherjacket
- Scientific name
- Brachaluteres ulvarum
- Japanese name
- アオサハギ
- Group
- Ocean animals
- Order
- Tetraodontiformes
- Family
- Monacanthidae
- Genus
- Brachaluteres
A member of the filefish family that lives on rocky shores and in beds of eelgrass, a kind of seagrass.
It is found along the Pacific coast of Japan from Ibaraki Prefecture to Yakushima, among other places.
How the Pygmy leatherjacket lives
Males follow females before they lay eggs. Pairs press their bellies against a large opening in a sponge to lay eggs. They do not guard the eggs after spawning.
東京大学Basic data
- Size
- about 10 cm
- Range
- Pacific coast from Ibaraki to Yakushima, Sea of Japan coast of Yamaguchi, Okinoshima and Tsuyazaki in Fukuoka
Where the Pygmy leatherjacket has been recorded
Records: GBIF.org (CC0 and CC BY 4.0 records, retrieved 2026-11-07). Map: Natural EarthSee the records on GBIF
Watch wild animals from a distance. Do not touch or feed them, and take care of the places where they live.
Names around the world
- 日本語
- アオサハギ
- 简体中文
- 绿短革单棘鲀
- 繁體中文
- 綠短革單棘魨
- 한국어
- 꼬마쥐치
- Português (Brasil)
- Peixe-porco-pigmeu-japonês
- Italiano
- Pesce lima pigmeo giapponese
Names come from Wikidata and iNaturalist records. Where a language has no recorded name, we use the scientific name.
Sources and how we check
- 鳥羽水族館 — アオサハギChecked: 2026-11-04
- 市立しものせき水族館 海響館 — アオサハギChecked: 2026-11-07
- 東京大学 — アミメハギの繁殖行動に関する研究Checked: 2026-11-07
We check each fact against its source. The illustrations simplify how the real animal looks.
The classification (class, order, family, genus) follows Wikidata records, checked against GBIF. Classifications can change as research goes on.
The basic data are the values given in each source. They vary with how the animal is measured, whether it is male or female, and whether it lives in the wild or in captivity.
This page was translated from the original Japanese with the help of AI.
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