Wallago catfish (boal, freshwater shark)

A long, scaleless catfish shaped like a knife: tall head, a huge mouth that splits back past the eyes and is lined with rows of sharp teeth, two pairs of barbels (one long pair on the upper jaw), a tiny dorsal fin and a very long anal fin running back to the tail. Silvery gray to greenish.

3–20 lb.

About 8 ft (240 cm); big fish weigh well over 50 lb.

Fish above all, plus shrimp and frogs; a fierce predator.

Hides in holes and under the banks of deep, slow rivers, canals and lakes and ambushes fish, mainly at dusk and night. Moves into flooded areas in the rainy season.

Found from India, Sri Lanka, Maldives & Pakistan, Southeast Asia (Thailand, Malaysia, Vietnam) and Indonesia (Bali, Komodo, Raja Ampat, Sulawesi). From Pakistan and India (Ganges, Indus, Brahmaputra, Krishna, Cauvery) through Bangladesh, Sri Lanka, Myanmar and Thailand to Vietnam (Mekong), Malaysia, Sumatra and Java.

From Pakistan and India (Ganges, Indus, Brahmaputra, Krishna, Cauvery) through Bangladesh, Sri Lanka, Myanmar and Thailand to Vietnam (Mekong), Malaysia, Sumatra and Java.

3–30 ft over mud and silt.

Deep, slow pools, undercut banks and reservoir drop-offs.

Year-round; best before the monsoon and as rivers fall after it.

Dusk, night and dawn.

No tide on rivers; in tidal lower rivers, moving water helps.

Warm, overcast weather.

Live or dead fish, fish strips and frogs.

Deep-diving crankbaits, soft swimbaits and spinners, especially at dusk; often caught in Thai fishing parks on lures.

Medium-heavy 7–8 ft spinning or baitcasting rod.

4/0–8/0 circle or J hooks.

30–50 lb braid.

50–80 lb mono or light wire — the teeth chew through light line.

Fish a live or dead fish on the bottom near deep holes and undercut banks at dusk and into the night, or work deep crankbaits slowly along drop-offs.

Wallago often grab the bait and swim off slowly — wait until the line starts moving steadily before setting the hook.

Catch and release: wet your hands, keep the fish in the water when you can, and release it quickly. Use circle hooks and a dehooker.

Good eating when fresh.

Bleed and ice it right away. Fillet, then remove the skin and any dark bloodline.

Popular food fish in India and Bangladesh (boal) — curried or fried.

A mouth full of sharp, backward-pointing teeth — use long pliers and a lip grip.

Listed as Vulnerable by the IUCN because of overfishing and dams; local state or country rules apply. Releasing big fish helps. In India, river fishing rules are set by each state, and many mahseer rivers are run by forest departments, angling associations or camps that sell permits and require catch-and-release; Nepal, Pakistan and Bhutan have their own permit systems.

Release large wallago; populations have dropped across its range.