Reservoirs are one of the most constructions for control and water supply for different usage that could have various social an economical effects . The Khandaghloo dam reservoir with area of 100 ha located in Mahneshan city of Zanjan province and related to Parichay river watershed.Khandaghloo reservoir is valuable water body that the aim of its establishment was supply of water for agriculture farms. The reservoir has been studied for responsible and sustainable fisheries exploitation proposes. Results showed that the reservoir categorizes as eutroph to super eutroph based on different indices.Also phosphorous is limiting factor of the water body.Totally 42 genera from 6 phyla including green-blue algae cyanophyta , diatoms (Bacillariophyta ) , green algae ,chlorophyta , euglenophyta ,pyrrophyta and xanthophyta has been identified and cyanophyta was the dominant group that comprise 74.3 % of phytoplankton population . The zooplankton of the reservoir comprised 4 phyla and 20 genera .1 genera of the protozoa and rhizopoda , 1 genra of the ciliophora ,15 genera of rotatoria , 2 genera of cladocera has been identified in zooplankton communities . Tubificidae and chironomidae has been identified in all months of the survey . The mean total length of crayfish was 130.5 ± 20.5 mm ( 636) and mean weight was measured as 69.4 ± 34.1 g with maximum and minimum weight of 1.9 and 207.2 g respectively .Total biomass of crayfish in Khandaghloo reservoir estimated as 3.4 tones with a range of 1.1 – 5.7 tones . But it is recommended not to harvest for at least two year due to high mortality of the populations.The fishes of the reservoir comprised common carp Chinese carp ( silver carp, big head and grass carp) ( released ) ,Caspian kutum ( accidentally released by fishery sector ) and some endemic species as Siamahii.The catch of the reservoir fluctuated between 8 to 26 tones during 2000-2010.The fish production of Khandaghloo reservoir ranged from 167 to 324 kg/ha based on different methods that by consideration of 100 ha area of the reservoir , the total production of fish fluctuated between 16.7 to 32.4 tones . The fingerling restocking of Chinese carp in Khandaghloo reservoir with density of 1500 fingerling/ha recommended as 68% of phytoplanktonivorous fish ( silver carp ) ,12% zooplanktonivorous fish ( big head ) , 6.6% of Crass carp and 10% of benthophagous fish ( common carp). Iranian Fisheries Science Research Institute Published