Fig. 7
Body deep; greatest depth contained 2.4 to 2.9 and caudal peduncle depth 8.0 to 9.8 times in SL; head length 3.2 to 3.6, predorsal distance 1.8 to 1.9 and caudal peduncle length 10.6 to 11.2 in SL; snout length 4.1 to 4.9, horizontal orbital diameter 2.4 to 3.0 and least interorbital width 2.6 to 3.0 in HL. Mouth terminal; inner row of premaxilla with 5 teeth, outer with 4 or 5, dentary with 10-12, and maxilla with one tooth. Lateral line complete, with 33-35 pored scales; transverse series above lateral line with 6 or 7 scale rows and below with 4 or 5 scale rows. Dorsal fin with 11 rays, pectoral fin with 12 or 13, pelvic fin with 7 or 8, anal fin with 27-30, and caudal fin with 19 rays. Ground color silvery; silvery longitudinal band on flank (brown or grey in fixed specimens), from humeral blotch to median caudal-fin rays, larger on caudal peduncle, forming oval-shaped, horizontally elongated, blotch; flank scales with dark-brown border.
Maximum standard length. 41.3 mm.
Biological data. Feeds on arthropods, debris and seeds of vascular plants and filamentous algae ( Castro, Vari, 2004a).
Distribution. Upper rio Paraná basin.