Bloch & Schneider, 1801
Wallago attu (Thai: ปลาเค้าขาว) is a species of catfish in the family Siluridae, or "sheatfishes". The fish is commonly known by its genus name, wallago or 'lanchi'. It is found in large rivers and lakes in much of the Indian Subcontinent and in parts of Southeast Asia. The species can reach 2.4 m (8 feet) total length. It ranges mainly across India, Nepal, Bangladesh and Sri Lanka, but is also found in Thailand, Cambodia, Vietnam and Malaysia, and is also reported from Afghanistan.
In Bengal and Assam, it is known as Boal and Borali. In Manipur it is commonly known by its local name "Sareng" or Valah in Malayalam respectively. In Indonesia and Malaysia, the wallago is known as "Ikan Tapah," and this name is the origin of the name of a Malaysian town, Tapah. In northern India it is known as buari. It is also known as Wallagonia attu, Boal Fish etc. Other names of the Sareng include the Mully Catfish, and Freshwater Shark due to its ferocity; and Helicopter Catfish. 
It is common to find huge frogs and fishes inside its stomach, when cut open for cooking. It has been claimed that in some areas of Thailand the natives fear the species because of its believed habit of eating small chickens and ducks, dogs, and small children. It is thought the Tapah became this aggressive due to natives laying to rest their dead in the water. The catfish would then see this as a ready supply of food.
Just like salmon, these fish do their annual upstream journey to lay their eggs during the monsoon season before returning to the deeper part of the river for the rest of the year. This is the time they fall prey to the local fishermen who set a special fish net across the river to trap the homecoming school. It was a common story amongst local Iban native of Sarawak that they speared several fishes weighing more than 50 kg each.
Following to some folklore in Malaysia, the descendant of a person called Tok Kaduk cannot eat and touch the fish because the legend says that a long time ago Tok Kaduk caught this Tapah and when he cut open its stomach, there was gold inside the fish so Tok Kaduk took the gold and stitched back the fish and released it back in to the river. From that time, if the descendant came in touch with the fish their skin would become red and itching until they go to Lambo near Bota in middle District of Perak, Malaysia to find the medicine. The medicine is remaining gold from the fish that has been kept to make the medicine for this disease. Some say that the gold needs to be soaked inside water and needs to be consumed by the patient and wash the areas that itch. Other stories have told that the Sareng will devour the carcass of humans that have been buried in the water, and it will take the human's soul to the gods.
- Tropical Storm Tapah (disambiguation) - Tropical Cyclones named for the Tapah.
- Ng, H.H. (2010). "Wallago attu". IUCN Red List of Threatened Species. Version 2012.2. International Union for Conservation of Nature. Retrieved 4 March 2013.
- "Wallago attu (Helicopter Catfish): Species profile". Seriously Fish.
- Magallanes, Frank. "Wallago Attu, Man Eating Catfish". Retrieved 2007-09-27.