This species is distinguished from all its congeners except G. australis and G. caaguazuensis, by the presence of a hyaline to grey anterior portion of the dorsal fin; differs from caaguazuensis by having a longer caudal peduncle, caudal fin not lyrate, central portion of scales on dorsal part of trunk light iridescent blue and white spots in soft portion of dorsal fin in adult males; differs from australis by the light iridescent blue coloration of central area of scales on the dorsal portion of trunk and tail, and by the absence of scales on the soft portion of the dorsal fin. It is further distinguished by the following unique set of characters: D 10-11 branched rays; 27-30 E1 scales; absence of lips thickening; adult males with a hump, with large white spots forming transversal stripes distally and in anterior area of the dorsal fin’s soft portion, absence of a conspicuous and oblique dark band from the eye to the anterior border of the head, anterior part of dorsal fin hyaline to grey, scales of the midlateral spot each bearing a semicircular light blue blotch, the head hump start at the horizontal through the eyes, concave anterior profile in lateral view, base of unpaired fins yellow, and whitish hyaline spots on caudal fin (Ref. 119666).