What does ayu mean?
Ayu is the Japanese name for Plecoglossus altivelis, a small, slender fish native to the rivers of East Asia that has become the standard English term for the species in culinary and angling contexts. Often called the 'sweetfish' because its flesh carries a delicate, melon- or cucumber-like sweetness, the ayu lives much of its life in fast-flowing freshwater before migrating to the sea and returning to spawn, a pattern similar to that of salmon. In Japan it holds a cherished cultural place: it is grilled whole with salt at summer gatherings, fished with trained cormorants in centuries-old ceremonies, and even caught using live decoy fish in a distinctive traditional technique. Because the ayu feeds on algae clinging to stones, it thrives only in clean, well-oxygenated rivers, so its presence is often taken as a sign of healthy waterways.
nounAyu is a small, slender freshwater and anadromous food fish (Plecoglossus altivelis) native to East Asia, prized in Japan for its sweet flavour and known there as the 'sweetfish'.
- The sweetfish Plecoglossus altivelis, an anadromous salmonid-like fish of East Asia, valued as food especially in Japan.
"Grilled over charcoal with a dusting of salt, ayu is a celebrated delicacy at summer festivals in Japan."
"Anglers lined the clear mountain river each summer to catch ayu using traditional cormorant-fishing methods."
"The restaurant specialises in shioyaki ayu, skewered and salt-grilled whole over hot coals."
Rarely needed in English; the word typically appears as a mass noun when describing the fish as food, and the singular suffices when naming the species.
"The stream was teeming with young ayus feeding on algae-covered rocks."
The ayu is so devoted to clean water that it can't survive in polluted rivers — making it both a delicacy and a living test of stream health.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of ayu
The word 'ayu' comes directly from the Japanese name for the fish, written variously as 鮎 or 香魚 ('fragrant fish'). It entered English as a naturalised loanword through writings on Japanese natural history, cuisine, and sport fishing, likely from the late nineteenth century onward as Western contact with Japan deepened. Its deeper ancestry lies within the Japonic language family, though secure cognates outside Japanese are limited.
How ayu is actually used
In English-language writing about Japanese cuisine and angling, 'ayu' functions as a loanword and usually appears unitalicised. It is sometimes glossed as 'sweetfish', which is the closest English common name.
Easily confused with ayu
'Ayu' is also used as a given name (most famously for Japanese singer Ayumi Hamasaki's nickname 'Ayu'), but as a dictionary word it refers to the fish rather than any person.