190 fish species (182 native and 8 exotics) belonging to 133 genera, 62 families and 23 orders was recorded from the entire stretch of River Ganga.  Review of past literatures show evidence of the fish richness of the Ganga River are not homogeneous and changing trends are reported after the descriptions elucidated by Hamilton in 1822. However, more or less similar pattern of fish species richness was observed during the studies conducted after 1990’s in case of Indo Gangetic plain Overall, Cyprinidae the most well represented and commercially important family constituting carps and minnows was recorded in all the freshwater section (up to site S16). Out of the total of the 62 families, Cyprinidae was found to be the most species rich (28 spp., 14.28%) followed by Danionidae (19 spp., 9.69%), Sisoridae (10 spp., 5.10%) and Bagridae (9 spp., 4.59%) respectively. River Ganga supports substantial percentages of food fish (60.84%), followed by ornamental fish (35.44%) and sports fish (3.70%). 55.78 % of the fish species is solely freshwater inhabitants. Around 15.26% of the fishes of the river are cosmopolitan in distribution inhabiting freshwater, brackishwater and marinewater ecosystems. Subsequently, only 18.94% of the species belong purely to the brackishwater and marinewater habitat. About 10% of the fish fauna are the mix of freshwater and brackishwater environments that consists of 14 families and 15 genera.

The prominent characteristic species are the Barb, Baril and minnows. The keystone species of the hilly stretch are Mahaseer (Tor putitora) and Snow trout (Schizothorax richardsonii). Downward of Haridwar to the plains up to Bhagalpur marks the appearances of commercially important fish groups of carps and catfishes. Species representing the higher economic value in the stretch are Labeo rohita, L. catla, Cirrhinus mrigala, L. calbasu, Sperata aor, S.  seenghala, Wallago attu, Chitala chitala, Rita rita, Eutropiicthys vacha and Clupisoma garua. Site Bijnor (106) and Narora (93) recorded the highest number of species followed by Prayagraj (85), Varanasi (84) and Farakka (84). 103 fish species were recorded  from Kanpur to Farakka stretch of the river. The lower zone of Ganga from Buxar (Bihar) to Tribeni (West Bengal) of the river is rich in from a biodiversity point of view supporting 123 fish species (118 native and 5 exotics).