Diagnosis: both males and females are readily distinguished from Rivulus cylindraceus by the presence of a dark lateral band situated longitudinally along the lateral line, extended from the posterior margin of the eye to the base of the caudal fin; dorsal fin slightly shifted to the caudal peduncle in relation to the origin of anal fin (1–3mm) when compared to Rivulus cylindraceus; frontal scalation pattern in Rivulus berovidesi sp. n. is d-type vs. e-type pattern in Rivulus cylindraceus (Ref. 101368).

Description: body subcylindrical anteriorly and compressed posteriorly; dorsal profile slightly convex from the snout to the posterior base of dorsal fin; ventral profile slightly convex from the lower jaw to the anal fin origin; both paired and impaired fins rounded and without filaments; dorsal fin origin above base of the 5th or 6th anal fin ray; pectoral fins inserted behind to the posterior margin of opercles; pelvic fins are the smallest, reaching anus; caudal fin rays 15–19; body and head entirely scaled with cycloid scales; longitudinal series of scales 34–37; transverse series of scales 9; pre-dorsal scales 21–25; frontal scalation is d-type pattern (Ref. 101368).

Coloration: Color in life: males body coloration is greenish or olive-green dorsally; wide dark lateral band extended from the posterior margin of the eye to the base of the caudal fin; ventral ground coloration is yellowish with orange spots reaching the anal fin base; an iridescent blue spot is present behind the margin of opercle in both sexes; males have an iridescent olive- green spot on the opercle too; dorsal fin is greenish, caudal fin is slightly greenish on its base and more transparent to the edges; anal fin is spotted in orange in their base and yellow or yellow- green to the ends; pelvic fins are yellow and pectoral fins are transparent (Ref. 101368). Females body coloration less striking when compared to males; general body coloration brown, darker dorsally than ventrally; ventral coloration is paler with some small yellowish spots; a narrow dark lateral band extended from the posterior margin of the eye to the base of the caudal; diffuse ocellated caudal spot present which can extends from the posterior base of dorsal fin to the superior margin of caudal fin and sometimes along the caudal fin base too; all fins slightly greenish or transparent (Ref. 101368). Color in preserved specimens: Preserved specimens with the typical dark lateral band from the posterior margin of the eye to the base of caudal fin in both sexes, although slightly paler than living specimens; ventral region of the body with a yellowish homogeneous coloration while dorsal region is brownish-gray; all fins with a whitish coloration (Ref. 101368). Males with a reticulated pattern on scales above lateral dark band (Ref. 101368). Females with the diffuse ocellated caudal spot extended from the end of dorsal fin to the superior margin of caudal fin (Ref. 101368).