Abstract
Hue-discriminatory capacity has been tested in three air-breathing teleosts, Channa punctatus, Clarias batrachus and Heteropneustes fossilis.Channa with well-developed eyes and efficiency of vision was successfully trained to discriminate red from green, blue, yellow, grey.and violet.It also distinguished violet from blue, green and grey as well as green from blue.The colour vision mechanism in this fish is mediated through trichromasy.The mud dwellers Clarias batrachus and Heteropneustes fossilis with markedly reduced eyes, showed poor colour-discrimination capacity, and perhaps barbels were evolved in these fishes to compensate their poor power of vision.
