Sea firefly
Amazing fact
When many sea fireflies gather on a small fish, they may eat it down to the bones.
葛西臨海水族園
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An illustration based on the real animal.
A little discovery to share.
When many sea fireflies gather on a small fish, they may eat it down to the bones.
THE REAL WORLD
The real Sea firefly
- Scientific name
- Vargula hilgendorfii
- Japanese name
- ウミホタル
- Group
- Ocean animals
- Class
- Ostracoda
- Order
- Myodocopida
- Family
- Cypridinidae
- Genus
- Vargula
Despite its name, it is not an insect like a firefly; it is a crustacean, in the same group as shrimp and crabs.
By day it stays buried in the sand; at night it swims out to find food such as dead fish and marine worms.
How the Sea firefly lives
They also eat weakened animals.
葛西臨海水族園Basic data
- Size
- Shell size: 3 mm
- Active
- At night (nocturnal)
- Diet
- Dead fish and crustaceans, ragworms, and other foods
- Range
- Japanese coasts except Hokkaido and the Pacific coast of Tohoku
Where the Sea firefly 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
Names come from Wikidata and iNaturalist records. Where a language has no recorded name, we use the scientific name.
Sources and how we check
- 葛西臨海水族園 — ウミホタルChecked: 2026-11-03
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.
Report a mistakeEXHIBIT INFORMATION
Places that keep or show the Sea firefly
Zoos, aquariums and other places whose official websites say they keep or show this animal.
Kanto
Displays can change with the animals’ health and the seasons. Check each facility’s official website before you go.
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