58.1 cm SL (male/unsexed; (Ref. 55106)); max. published weight: 32.7 kg (Ref. 72380)
Brachyplatystoma capapretum is characterized by the following features of which the first three are unique among the Pimelodidaeand the last is unique among the rachyplatystomatini.1. Jaw teeth dimorphic with mostly fine, denselyspaced outer teeth and relatively few (three to six) inner rows of slender, straight, inwardlydepressible teeth.2. Juveniles (less than 200 mm SL, but some aslarge as 300 mm SL) marked by bold, large(twice or more times eye diameter) dark brown or gray spots centered above lateral line; ground color in preservative tan to medium brown.3. Adults and juveniles (more than ca. 200 mmSL) black to very dark gray or brown dorsallyand abruptly countershaded along a horizontalfrom snout tip to caudal-fin base, especiallyalong posterior half of body just above or at lateral line; ventrally plain white to dusky cream; most specimens with light patch anterior to upper lobe of caudal fin.4. Caudal fin of adults moderately to shallowlyforked, lobes broad and nearly equal.