This species (belonging to the subgenus Guianacara) can be distinguished from G. oelemariensis (subgenus Oelemaria) by the possession of 2 supraneural bones, produced dorsal-fin lappets and a midlateral bar. It is distinguished from all other species in the subgenus Guianacara by the possession of an infraorbital stripe that progressively fades across the cheek (from just beneath the eye to the dorsal edge of the pre-opercle) in individuals which are more than 45 mm SL, but remains black or dark brown across the preopercle and interopercle (vs. infraorbital stripe continuous throughout ontogeny); posterior half of the lower pharyngeal jaw toothplate with a dorsally edentulous laminar expansion of the lateral margin (vs. absent in other species of Guianacara). G. dacrya can by further distinguished from G. stergiosi, G. sphenozona, G. owroewefi and G. geayi by the possession of a thin midlateral bar which covers three scales at its widest point, thinning to 1.5 to 2 scales (vs. never less than 3 scales); from G. geayi and G. sphenozona, by the retention of the juvenile dark coloration of the 3 anterior dorsal-fin spines and lappets in adults (vs. lost); from G. owroewefi and G. sphenozona by the possession of white spots on both the soft and spiny portions of the dorsal-fin; from G. stergiosi and G. cuyunii by a larger eye, a shorter and narrower head, shorter pectoral fin and by produced filaments of the anal, dorsal and (occasionally) caudal fins; from adult G. cuyunii by a distinct midlateral spot, the possession of dusky branchiostegal membranes and a shallower body; from adult G. stergiosi by a shorter preorbital region and longer pelvic fins. In G. dacrya, when a midlateral spot is distinguishable, it is small, round and placed on and below the upper lateral line, similar to G. stergiosi (vs. large and oval shaped (G. owroewefi) or placed on and above the upper lateral line (G. sphenozona) (Ref. 86674).