Chrysobrycon eliasi is distinguished from its congeners by the maxillary teeth, tricuspidates, bicuspidates, and conical, vs. all maxillary teeth tricuspidate to pentacuspidate in C. myersi and C. hesperus. Chrysobrycon eliasi also has the terminal lateral-line tube developed between caudal-fin rays 10-11 vs. absence of the terminal lateral-line tube in C. myersi and C. hesperus. Furthermore, Chrysobrycon eliasi differs from C. hesperus by the presence of 6-15 (mode = 11; n = 28) maxillary teeth occupying more than 70% of the length of the maxilla in adults, vs. maxilla with 2-9 teeth (mode = 3; n = 11) occupying less than 70% of its length in adults, and a lower number of predorsal scales 18-22 (mode = 19; n = 28) vs. 22-23 (mode = 22; n = 11), respectively. Chrysobrycon eliasi is also readily differentiated from C. myersi by a smaller dorsal-fin to hypural complex length 36.32-41.17% SL vs. 42.19-47.38% SL; smaller gill-gland length in males, 3.57-5.05% SL vs. 6.52-6.66% SL; shorter maxillary length, 33.76-38.75% HL vs. 39.85-48.28% HL; and a lower number of branched anal-fin rays, 24-30 vs. 33-36. Chrysobrycon eliasi has a different pattern of scales near to the pouch scale of males; the additional small scale is set under the pouch scale and its ventral border is not seen in the lateral view (Ref. 88954).