Dorsal spines (total): 2; Dorsal soft rays (total): 7 – 8; Anal soft rays: 35; Vertebrae: 48. Body without stripes; posterior nostril located near anterior nostril; 7 branched dorsal-fin rays; gill rakers rudimentary or absent; fins grey, never black. The center of the eye above the horizontal line through the mouth angle in juveniles; eye totally below the level of mouth angle in subadults and adults. The maxillary and mandibulary pairs of barbels well developed in juveniles; mandibulary barbels become rudimentary in subadults and adults. Gigantic size; oral teeth and gill rakers present in small juveniles, absent at about 30-50 cm SL; dorsal, pelvic and pectoral fins without filamentous extensions. Distinguished from other large catfish in the Mekong by its lack of teeth and the almost complete absence of barbels. Body shape (shape guide): elongated; Cross section: circular.