Fish · GBIF taxon 4283980
Ayu
Plecoglossus altivelisAlso known as Ayu Sweetfish, Sweetfish
Ayu are amphidromous fish native to East Asia, spending winter in coastal marine waters before migrating up clear rivers in spring. Adults establish distinct territories on sunlit riverbed stones, using comb-like teeth to scrape off algae and diatoms. Famous for producing a natural fragrance reminiscent of sweet watermelon or cucumber, they hold a prominent place in regional river ecology and culture.
AmphidromousMigratoryFreshwater
—observations
—countries
—peak records
Data DeficientConservation statusIUCN Red List categoriesLCNTVUENCREWEXData Deficient — not placed on the risk ladderRed List categories, explained →
Diet & prey
- Benthic Algae
- Diatoms
- Mayfly Larvae
Predators
- Grey Heron
- Crested Kingfisher
- Largemouth Bass
ThreatsDam construction, water pollution, and habitat degradation
HabitatsClear coastal streams, rivers, and estuaries
Life span1–3 years
Size / weightNot available
Classification
- FamilyPlecoglossidae
- SpeciesPlecoglossus altivelis
Range data is not available yet.
Interaction riskLow
- Low
- Moderate
- High
- Very high
- Why interaction risk is low
- Safe to observe at a normal distance.
- What to notice
- Recognizable by an olive-green back, golden patch behind the gill cover, and bright yellow fins.
- Support conservation
- Observe quietly from riverbanks or bridges without wading through gravel spawning beds.
Responsible observation
- Observation: Look for territorial grazing tracks on algae-covered river stones.
- Seasonal Timing: Watch for migrating juveniles in lower river reaches during spring.
River Companion opencage / CC BY-SA 2.5 · CC BY-SA 2.5
Predator (c) Jagdish Singh Negi, some rights reserved (CC BY) · cc-by
Close Relative (c) Sean Vanderluit, some rights reserved (CC BY) · cc-by
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