Difficult to distinguish from C. elephas. From key published in Poll, Gosse, & Orts, 1982:
-C. elephas: SL 5.8-7.3x in snout length. Chin barbel not tapered, obtuse, equal of longer than eye (0.9-1.5x), generally inserted above the lower lip. Body depth 3.3-3.8x in postocular standard length. Snout angle 35°-61°
-C. alces: SL is 7-8.5x in snout length. Chin barbel is tapered and pointed, shorter, equal or a little longer than eye (0.7-1.3x), not inserted above the lower lip. Body depth 2.8-3.3x in postocular standard length. Snout angle 56°-71°.
Upper Congo Rapids from Boyoma Falls (Stanley Falls), Kisangani, D.R. Congo to Ubundu (ex-Ponthiereville). Also some records from Stanley Pool and Lower Congo at Matadi. Poll (1967) reports and illustrates this species (or something resembling it) from the rapids of the Luachimo River near Dundo, Angola. See occurrence records on FishBase.