Wallago

The helicopter catfish, Wallago attu, is a giant predatory catfish found through much of Asia, from Afghanistan and Pakistan to Indonesia. It can reach 240 cm, and its mouth is filled with needle-sharp, backward-pointing teeth. It will bite aggressively when fed or handled, and the profile treats it as a genuinely dangerous fish that is clearly not an aquarium species.

The striped wallago catfish, Wallago leerii, is a large predatory catfish from southeast Asia, including the Mekong basin, that can reach 2 metres. Like all Wallago it has an enormous mouth full of backward pointing teeth, and smaller fish are simply swallowed whole. This is NOT an aquarium fish, though it is imported quite regularly at a small size. In nature it is migratory and moves into inundated forest during the rainy season.