Dorsal soft rays (total): 8; Analsoft rays: 19 - 23; Vertebrae: 41 - 43
10.0 cm SL (male/unsexed; (Ref. 38376))
This species is distinguished from its congeners, except H. jelskii, by the size of humeral spot over 7-8 horizontal series of scales (vs. 3-6). H. helleri differs from H. jelskii by the number of branched anal-fin rays (19-23 vs. 25-30), and number of scales along anal-fin base scale sheath (6-12 vs. 13-28). It is rather similar to H. inambari, but can be distinguished by the size of humeral spot (over 7-8 vs. 5-6 horizontal series of scales), number of predorsal scales (16-18 vs. 13-16), and by the total number of vertebrae (41-43 vs. 39-40) (Ref. 85819).