Economidis and Nalbant (1996) discuss characters used in the study of these fishes and consider scales to be characteristic of each species along with colour pattern, sexual dimorphism, suborbital spine morphology, barbel and mental lobe morphology, and others.
Black spots at the caudal fin base and four longitudinal pigment zones on the flank (Z1-4 or Gambetta's zones 1-4) are important in distinguishing and describing species.
Genus Cobitis Linnaeus, 1758 These fishes are found in Europe, North Africa and Asia. They are known generally as سگ ماهي (sag mahi meaning dog fish) in Farsi, the equivalent of loach in English.
Menon (1992) considers that structural details of the bony covering of the swimbladder and the nature of the scales are only of use at the generic level.
Lip structures, fin positions relative to one another and secondary sexual characteristics in males are important characters in differentiating species in India.
They take in air at the surface, and pass it through the intestine where the mucosa absorbs the oxygen and carbon dioxide waste is released through the vent.
As a consequence, they may be very sensitive to air pressure changes and become restless when it falls and can be used to predict the weather.
Maximum size is about 40 cm but most are much smaller.