Freshwater · Late spring to early autumn; night fishing best

Korean Bullhead

Tachysurus koreanus

A big-eyed endemic bagrid catfish of Korea's clear rivers — 눈동자개 literally means 'big-eyed catfish' and the eyes are the first thing you notice. Night-active and social, it is the perfect small river catfish for simple after-dark worm fishing.

Seasons · Peak

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Korean Bullhead — AI-generated image — AI-generated image — no verified freely-licensed photo of this species was available

Identifying features

Yellowish to brownish scaleless skin, 4 pairs of barbels
Large dark eyes — hence the Korean name 눈동자개 ('big-eyed catfish')
Forked tail fin and a moderately tall adipose fin
Shorter and stockier than the slender continental yellow catfish
Dorsal and pectoral spines strong and serrated

Habits

Night-active — hidden in deep pools by day
Social in small groups
A true endemic — known only from Korea
Omnivorous forager of insects, snails and small fish
Dorsal and pectoral spines give a painful sting — handle carefully

Distribution

Regional coverage expanding

Where to find them

Han River tributaries at Yangpyeong
Gokseong and Seomjin-system streams
Geum River pools at Gongju

Where they live

Clear rivers and streams across the Han, Geum and Nakdong systemsDeep pools under rocks and tree rootsSand-gravel transitions in slower river reaches

How to catch them

Night fishing at river pools River

Rig: Bottom rig with a big worm on a size 6 hook, set still in deep pools under rocks at night

Bait/lure: Large earthworm

Key tip: Fish come out of pools to forage after dark; lantern light reduces bites — darkness works best.

Bottom fishing at sand-gravel edges River

Rig: Medium rig with shrimp piece placed at the sand-to-gravel edge in moderate flow

Bait/lure: Shrimp or fish pieces

Key tip: Mind the spines — unhook with pliers and never grip the body with bare fingers.

Best baits & lures

EarthwormShrimp piecesFish pieces

Techniques for Korean Bullhead →

Baseline setup

Rod: Light 7-8 ft river rod
Line: 6-10 lb monofilament
Terminal: Hooks size 4-8, medium sinkers to suit the current

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 (15-22 cm); large fish about 10 in (25 cm)

On the table

Good in spicy stews; sharp dorsal and pectoral spines — unhook with care.

Similar species

Yellow CatfishYellow catfish (the continental yellow bagrid) is slimmer and paler with a smaller eye; Korean bullhead is a darker, big-eyed endemic of clear Korean rivers

Regulations 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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