Differs from all congeners by the combination of the following characters: a small median lobe of the rostral fold; lower lip distinctly covered with melanophores; 9-12 squarish blotches on side of body, their height about one-third body depth; and 85-89 lateral line scales. Can be diagnosed from Erromyzon sinensis by having 9-12 irregular blotches on body (vs. 17-21 very irregular bars or a mottled pattern); from

E. compactus by having lower lip with two or three folds (vs. folds absent), a midlateral row of squarish blotches on flank (vs. bars continuous across dorsum), and four rows of blackish spots on dorsal-fin rays, six rows on caudal-fin rays (vs. two rows on both dorsal and caudal-fin rays); and from E. yangi in having 85-89 lateral-line scales (vs. 96-99) and by its color pattern consisting of 9-12 blotches on flank (vs. a black midlateral stripe dark brown dorsum and an incomplete lower black stripe) (Ref. 93072).