An attempt has been made to assess the ichthyofaunal diversity of Alaknanda River which is known as one of a major river system of Uttarakhand state. Alaknanda originates from Satopanth glacier and contributes to the mighty river Ganga. The estimated total length of river network is 10927.9 kms including streams, tributaries and rivulets, which support occurrence of 83 fish species belonging to 39 genera. Conservation and restoration efforts on large rivers often focus on the main streams, but not for subsidiary tributaries, which provide unique habitat and serve as spawning sites and nursery grounds. Despite their abundance on the landscape and important role in ecosystem, tributaries are ignored in commonly used cartographic depictions, but play an important role in the ichthyofaunal diversity.