Centromochlus britskii can be diagnosed from all members of Centromochlinae, except Gelanoglanis nanonocticolus, by the absence (vs. presence) of adipose fin. It differs from G. nanonocticolus by having two pairs (vs. one pair) of mental barbels, premaxillary tooth patches anteriorly united (vs. separated) and mouth gape straight and short (vs. large and sinuous). It is distinguished from congeners Centromochlus altae, C. existimatus, C. heckelii, C. perugiae, C. reticulatus, C. romani and C. meridionalis by having seven branched anal-fin rays (vs. 5 or 6). It further differs from C. altae, C. existimatus, C. heckelii and C. perugiae by lacking anterior nuchal plate (vs. present); from C. meridionalis and C. romani by having anterior margin of dorsal-fin spine with serrae (vs. dorsal-fin spine smooth); from C. existimatus and C. heckelii by having shorter pectoral-fin spine 20.7-22.7% of SL (vs. 29.3-41.6% of SL). Among species group that share the absence of anterior nuchal plate and seven branched anal-fin rays (i.e, C. punctatus, C. schultzi, C. macracanthus, C. bockmanni, C. simplex), the new species Centromochlus britskii differs from both C. schultzi and C. macracanthus by having smooth (vs. with denticules) posterior border of dorsalfin spine; and from C. punctatus by the morphology of male modified anal fin, specifically, the last branched anal-fin ray progressively shorter than anterior most (vs. last ray abruptly reduced, size half that of preceding one and visible only through dissection) (Ref. 103263).