Eunotia enischna is considered to be a member of the E. exigua complex. Eunotia enischna is most similar to E. tenella but E. enischna are more finely striated, more slender, and have more distinctly recurved ends than E. tenella. Valves of E. enischna are more narrow and less distinctly constricted near the apices than the valves of E. exigua sensu stricto. Furthermore, the ventral margin of E. enishna is not as concave as the ventral margin of E. exigua.