Differs from all other species of Metzia in having the following characters: anal fin with 18-20 branched rays; scales on lateral line 49-55; predorsal scale rows 33-36; circumpeduncular scale rows 20-22; gill rakers on outer surface of first gill arch 8-10. Resembles species of Hemiculterella, Ischikauia and at least a part of Anabarilius in sharing a sharp keel restricted in development to the area between pelvic-fin base and anus, last unbranched dorsal-fin ray being soft, and an air bladder composed of two chambers. However, this species differs in having the following characters; a notably rounded snout (vs. pointed in Hemiculterella, Ischikauia and Anabarilius); 18-20 branched anal-fin rays (vs. 8-17 in Hemiculterella, Ischiakua and Anabarilius ); 49-55 lateral-line scales (vs. more than 58 in Ischikauia and Anabarilius, except for A. transmontana with 54-57); air bladder with rounded posterior end (vs. posterior end with a small lobe at least in Hemiculterella); and 39-40 vertebrae (vs. 40-43, 42-43 and 43-48 in Hemiculterella, Ischikauia and Anabarilius, respectively). Also similar to its sympatric species Paralaubuca barroni but can be readily distinguished by having 18-20 anal-fin rays (vs. 24-29 ) and 8-10 gill rakers (vs. 19-24) and a distinct keel between anus and a vertical through posterior end of pelvic-fin base, keel preceded by a very weak midventral, blunt ridge extending anteriorly to a vertical through posterior half of pectoral fin (vs. a distinct, complete abdominal keel extending from anus to isthmus) (Ref. 93140).