This argument gets started around the time the second Chang is opened. Someone has just caught a large Mekong catfish at Bungsamran and is describing the fight with the reverent specificity that only a very tired forearm produces. Someone else has just returned from Gillham's with an arapaima on their camera roll. Neither man is entirely wrong. Neither man is going to concede.
The Mekong giant catfish and the arapaima are the two fish most associated with Thailand's position as a destination for anglers who specifically travel to catch very large freshwater fish. They are both extraordinary animals. They fight in almost entirely opposite ways. And the question of which is harder is, like most genuinely interesting fishing arguments, unanswerable in absolute terms — but worth having properly, with the actual specifics on the table.
The arapaima will try to leave the lake. The Mekong catfish will try to take you into the earth. Neither is wrong about which direction they're going.
The Arapaima's Fight
The arapaima (Arapaima gigas) is an obligate air-breather, which means it must surface periodically to gulp air from an air-sac that functions like a lung. This biological necessity shapes everything about the way it fights.
The take: Arapaima at venues like Gillham's are typically fished on floating baits — chunks of fish fillet or specially prepared pellets that sit on or just below the surface. The take, when it comes from a large fish, is not subtle. There is a boil, a swirl, and then an immediate and violent commitment that leaves no room for doubt. The hookset on an arapaima is a deliberate, hard pull — these fish have bony, largely bone-plated mouths and a soft strike will not find purchase.
The first run: The immediate response of a fresh arapaima is horizontal speed. These fish run, and they run fast. Unlike many large freshwater fish that dive instinctively, the arapaima's first instinct is to cover distance at the surface, and in a lake of reasonable size they will test every metre of line the reel holds. Drags are set hard — 10–12kg of strike drag is normal on a large fish at Gillham's — and even so the runs are long enough to require repositioning.
The jump: This is the signature. A large arapaima, when it clears the water, produces a moment that anglers remember in specific, sensory detail for years. The fish clears the surface completely — four, five, six feet of prehistoric animal airborne — shakes its head with a violence that can throw even a well-set hook, crashes back with a detonation that spreads across the lake, and repeats. Multiple jumps are common. The fight is vertical as well as horizontal.
Stamina: The air-breathing adaptation that forces the fish to surface also, paradoxically, limits the length of a sustained fight. A large arapaima at full exertion tires within 20–40 minutes for most specimens, though very large fish — anything over 100kg — extend this considerably. The fight has peaks of extraordinary intensity punctuated by recoveries, and it is during those recoveries that inexperienced anglers give line back unnecessarily and extend the battle.
The Mekong Catfish's Fight
The Mekong giant catfish (Pangasianodon gigas) is a filter-feeder that reaches its extraordinary size on algae and detritus. It has no teeth, no aggression in any recognisable predatory sense, and no particular interest in the surface of the water. It fights entirely downward, and it does so with a dumb, geological patience that breaks tackle and backs far more often than any aerobatic display.
The take: At Bungsamran, Mekong catfish are targeted on heavy bottom rigs with fermented paste baits. The take is typically a slow, deliberate tightening of the line — the fish engulfs the bait without urgency and begins to move off. The strike is a powerful pull to drive the hook home through the cartilaginous pad that lines the upper mouth.
The dive: The fish's first response is straight down and away. There is no surface action, no lateral run, no jump to anticipate. The rod bends into a deep arc and stays there. The fish applies pressure in long, sustained pulls that feel less like a sprint and more like attempting to stop a vehicle from rolling. The drag screams in short bursts as the fish surges, then settles into a grinding, weight-against-weight contest.
The grind: This is the defining characteristic of a large Mekong catfish fight — the extended, exhausting middle period in which neither the fish nor the angler is gaining ground. The fish sits in its depth, using its enormous bulk and the angle of the water column as leverage. The angler pumps and winds, gains two feet, loses a foot. A fish in the 50–80kg range fought on appropriate tackle typically takes 30–60 minutes. A very large fish, 100kg-plus, can exceed two hours.
The end game: The catfish does not flag dramatically. It does not surface in a burst of energy before submission the way many large fish do. It slowly, gradually, inexorably runs out of reserve. The fish comes up reluctantly, often rolling at the surface before being guided to the net — a large, pale, oddly serene animal that has simply been worn down rather than defeated.
Side by Side
| | Arapaima | Mekong Catfish | |---|---|---| | First run | Long, fast, surface | Deep, powerful, vertical | | Jumps | Yes — spectacular | Never | | Stamina | 20–60 min typical | 45–120 min typical | | Fight style | Explosive, aerial | Grinding, sustained | | Primary venue | Gillham's (Krabi) | Bungsamran (Bangkok) | | Tackle demand | Heavy drag, strong hooks | Heavy bottom rig, long rod | | Surrender style | Sudden fatigue at surface | Slow, reluctant ascent |
Which Is Harder?
The honest answer — the one that survives past the second Chang — is that they test you differently, and which is "harder" depends entirely on your definition.
The arapaima is harder to handle. The explosive takes, the jumps, the changes of direction, the need to maintain constant pressure without over-pressuring a jumping fish — it demands more athleticism and reaction speed from the angler.
The Mekong catfish is harder to endure. An hour of sustained grinding pressure on a fish that simply refuses to come up, on arms and lower back that were already tired after twenty minutes, is a test of physical endurance that the arapaima fight, for all its drama, rarely extends to.
The arapaima tackle guide and the best rod for Mekong catfish reflect these differences in their hardware recommendations.
The better framing is this: if you have time in Thailand for both — and you should arrange your trip so you do — the question becomes irrelevant. You will fish Bungsamran for catfish and Gillham's for arapaima, or you will fish IT Lake Monsters for arapaima in Bangkok and Bungsamran on the same trip, and you will have two fights that are so different in character that comparing them feels, eventually, like comparing chess to boxing. Both are contests. Both are won by the same combination of preparation and composure. Both produce the kind of specific, embodied memories that are the actual reason serious anglers travel this far.
Continue the argument:
