Fish fauna of four zones of the Himalayas viz., Himalayan foot- hills, Lesser Himalayas, Great Himalayas, and Trans Himalayas was explored during the last twelve years. The studies resulted in 93 species from all the four zones. The areas included in the Trans-Himalayas and the Great Himalayas possessed only the cold water fish fauna belonging to the Subfamily Schizothoracinae and the genera Triplophysa and Glyptosternum. The Lesser Himalayas zone, although mainly possessing high altitude cold water fishes, was also found inhabited by many warm water species migrating upstream from submontane areas or plains. The Himalayan foot- hill fish fauna was almost the same as found in Indus plain. Zoogeographical relationships of high attitude fish fauna of these zones common with the fish fauna of the Central Asian drainage system were also highlighted.