Melanorivulus linearis is similar to M. egens, and differs from all other members of the M. pictus group by having red chevron-shaped marks regularly distributed on the flank (vs. irregularly), by lacking distinctive dark marks on humeral region (vs. presence), and by the absence of red dots on the anteroventral portion of flank (vs. presence). It can be diagnosed from M. egens by having the following characters: males with red bars restricted to the dorsal portion of the caudal fin (vs. absent); females with black bars on the caudal fin (vs. black dots); males with a pale green spot on humeral region (vs. absent); and second proximal radial of the dorsal fin located between neural spines of 18th and 19th vertebrae (vs. between neural spines of 19th and 21st vertebrae) (Ref. 116860).