Diagnosis: Lacustricola nitida is most similar to L. matthesi; both species share the overall diagnostic characters of body colour pattern with brilliant blue spots at scale centres, forming longitudinal lines on the flank, and creating a reflective blue body colouration; fin tips of anal- and dorsal-fin rays occasionally with narrow light blue margin in females; as well as cephalic sensory system characterized by the combination of supraorbital canal with exposed neuromasts in zigzag shaped continuous groove, at preorbital level in open groove with exposed neuromasts, whereas postorbital and preopercular sensory systems tubular with pores (Ref. 127235). Lacustricola nitida is distinguished from L. matthesi by the following unique combination of characters: dorsal and anal fins hyaline and without markings in males vs. yellow with irregularly curved dotted stripes; in both sexes, a supraorbital sensory system with three exposed neuromasts vs. four; smaller head length, 23.0-24.7% of standard length vs. 27.1-32.2%; smaller dorsal-fin base length, 8.9-12.5% of standard length vs. 15.1-18.2%; smaller postorbital length, 35-38% of head length vs. 41-45%; greater eye diameter, 43-47% of head length vs. 33-40%; larger caudal peduncle length, 171-194% in its depth vs. 130-155%; and less numerous rays in pectoral fin, 10-11 vs. 12-13 (Ref. 127235).

Description: Males: general body shape laterally compressed and moderately deep; small to medium sized species, maximum observed size 29.9 mm standard length; greatest vertical body depth in front of pelvic-fin origin and shallowest at mid-portion of caudal peduncle; greatest body width at pectoral-fin base with body progressively narrowing towards caudal-fin base; dorsal profile straight to slightly convex from snout to origin of dorsal fin; convex along dorsal-fin base, straight to slightly concave from base of dorsal fin to caudal fin; dorsal profile of larger males occasionally concave at nape; ventral profile convex from lower jaw to base of last anal-fin ray, straight to slightly concave on ventral midline of caudal peduncle; caudal peduncle relatively long, length 171-194% of its depth; anus directly in front of anal-fin origin (Ref. 127235). Head short, laterally compressed, deeper than wide, head width 76-80% of its depth; snout slightly rounded, smaller than eye diameter; mouth superior, oblique in profile; jaws not equal, lower jaw longer than upper, posterior end of corner of mouth at same level to centre of eye; premaxilla and dentary with many irregularly distributed conical teeth; orbit large, 43-47% of head length (Ref. 127235). Dorsal fin set rearwards, origin posterior to anal-fin origin, both fins originating posterior to mid-length of body; dorsal and anal fins rounded; dorsal fin with 8-10 rays, anal fin with 15-16 rays; pectoral fin subtriangular, insertion relatively high and posterior to margin of opercular opening; base oblique, upper fin rays placed anteriorly to lower fin rays, 10-11 rays; pelvic fin sub-abdominal; its origin slightly posterior to mid-length between insertions of pectoral and anal fins, almost reaching origin of anal fin; caudal fin large and truncate, with 12-13 branched rays, plus four or five dorsal and ventral procurrent rays (Ref. 127235). Scales cycloid, body and head entirely scaled, except for ventral surface of head; scales in midlongitudinal series 26-27, plus two or three small scales on caudal-fin base; transverse rows of scales in front of dorsal-fin origin 7; scale rows around caudal peduncle 12 (Ref. 127235). Frontal neuromast in shallow groove; cephalic sensory system at preorbital level in two discontinuous shallow grooves, with one and two neuromasts, respectively; infraorbital series with about a dozen small buttons; postorbital canal tubular with two pores; preopercular sensory systems tubular with seven pores; cephalic sensory system at supraorbital level in zigzag groove, usually with pronounced lobes, with three neuromasts, anteriormost one anteriorly displaced from the other two; whereas at supratemporal level in a strongly curved groove, with three exposed neuromasts, and groove connecting to pore of postorbital canal; mandibular canal in shallow open groove parallel to outer margin of lower jaw, with two exposed neuromasts (Ref. 127235). Females: body depth and head depth smaller than in males, body depth at pelvic-fin origin 25.0-25.2% of standard length vs. 26.8-28.9%, head depth 80-82% of head length vs. 83-85% respectively; head less laterally compressed than in males, head width 79-80% of its depth vs. 76-78% respectively; caudal peduncle shallower than in males, caudal peduncle depth 12.9-13.2% of standard length vs. 13.4-14.6%, caudal peduncle length 191-194% of its depth vs. 171-177% respectively (Ref. 127235).Colouration: Colouration of live males and females: scales on trunk with iridescent metallic blue, with a pattern of independent iridescent light blue spots along mid-longitudinal series and two or three series below on posteroventral portion of flank, creating an overall reflective blue body colouration; scales on dorsum above mid-longitudinal series completely grey, with sparse tiny blue iridescent dots; scales on abdomen from opercle to pelvic fin white to silver; head yellow to light brown-grey, snout and dorsal portion of head greyish brown, throat silver; exposed branchiostegal membrane white; iris silver, iridescent in upper portion; iridescent silver to blue blotch on postorbital opercular region; iridescent silver to blue humeral blotch on post-opercular region; dark grey blotches on scales of mid-longitudinal series; all fins hyaline; dorsal-fin membrane light grey along upper and lower margins in males; fin tips of some anal- and dorsal-fin rays occasionally with narrow light blue margin in females (Ref. 127235).