Freshwater · Summer through autumn in clear streams; many reaches have closed seasons — check local rules first
Ayu Sweetfish
Plecoglossus altivelis
The ayu is East Asia's fragrant stream jewel, famous for the tomozuri method — fishing with a live decoy ayu — and for its delicate, melon-scented flesh. In Japan it is the emblematic summer river fish, taken with the same tomozuri live-decoy method under local fishery-cooperative seasons.
Seasons · Peak
Identifying features
- Slender, silvery-olive stream fish with a small mouth and forked tail
- A small adipose fin between dorsal and tail, like a tiny trout
- Breeding fish turn yellow-orange with dark markings in autumn
- Scales are very small and the skin feels smooth and slippery
- No barbels and no dark spots along the flank
Habits
- Lives in clear mountain streams in Zhejiang, Fujian, Jiangxi and Taiwan and the Yalu River system
- Grazes algae from rocks as an adult, defending a feeding territory on the stones
- Young fish spend winter at sea or in estuaries and run up streams in spring
- Most adults die after spawning in autumn — a largely annual fish
- Many streams have closed seasons or protected reaches, so check local rules before fishing
Distribution
Regional coverage expanding
Where to find them
- Gravel riffles and runs of clear mountain streams
- Rocky pools where ayu graze algae from the stones
- Below small weirs on the spring upstream run
Where they live
How to catch them
Tomozuri decoy fishing River
Rig: Light stream rod, fine line, a live ayu on a fine circle-style hook rigged to swim naturally over a territory
Bait/lure: Live decoy ayu
Key tip: Work the decoy slowly across algae rocks; the territory holder attacks the intruder and hooks itself — where local rules allow this method.
Tenkara and fly fishing River
Rig: Tenkara or light fly rod, small weighted nymphs and wet flies dead-drifted in the runs
Bait/lure: Small nymphs, wet flies
Key tip: Drift the fly tight to the stones at dawn and dusk, when ayu leave their territories and take insects.
Best baits & lures
Baseline setup
- Rod: Light 9-12 ft stream or tenkara rod
- Line: 3-6 lb mono or fine tippet
- Terminal: Fine small hooks, small nymphs and wet flies, live-ayu rig where legal
Recommended gear for this species
Rod · Best value
9' 5-weight fly rod outfit
≈ US$180-260
Covers chironomid lakes and small rivers with one setup.
Flies · Budget
Chironomid assortment (30 patterns)
≈ US$25-40
Chironomids are 60% of a lake rainbow's diet in spring.
Picks come from our rule library — never paid placements. Prices are guides; affiliate links may earn us a commission.
Typical size
Common 6-9 in; large fish to about 12 in and under 1 lb
On the table
Excellent — prized for its sweet, fragrant flesh; handle protected or closed-season fish strictly by local rules and release where required.
Similar species
Ussuri WhitefishUssuri whitefish is a larger, deeper-bodied coregonid of cold northern rivers with a much smaller, toothless mouth; ayu is a slender southern mountain-stream fish with an adipose fin and algae-grazing habits
Amur GraylingAmur grayling has a huge, sail-like spotted dorsal fin; ayu has a small, plain dorsal fin and only the tiny adipose fin behind itRegulations vary by area and can change in-season — always check the official rules for your area before you fish. Regulations guide →
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