Scorpiodoras heckelii is diagnosed from its two congeners S. calderonensis and S. liophysus by having a relatively large eye, diameter 91-129% of interorbital width (vs. relatively small eye, diameter 58-93% of interorbital width). It further differs from these congeners by the

having a simple, egg-shaped, secondary bladder without terminal diverticulum (vs. secondary bladder absent in S. liophysus and with terminal diverticulum in S. calderonensis) and from S. liophysus by presenting a relatively shallow scute depth (33-51% of body depth near anal-fin origin, vs. 61-72%) (Ref. 86601).

Description: anal fin v-vi,8-10 (Ref. 86601).