Ptychidio jordani, the ratmouth barbel, is a species of freshwater, ray-finned fish from the carp family, Cyprinidae.

It is endemic to the Pearl River drainage system, purported records from Taiwan being considered extremely doubtful.

It has been a highly sought species for fisheries but the population has declined to such an extent that it is now rarely caught and the damming of its native streams and rivers is now the chief threat to this species.

It is a demersal species which feeds on molluscs and algae.

[2] The specific name jordani was applied by George S. Myers in honor of ichthyologist David Starr Jordan in appreciation of his friendship and kindness to Myers.