Abstract: The survey was undertaken during the period from October -2012 to September -2013 in the Vattakkayal, Sakthikulangara panchayath, Kollam district. The major objective of this study was to find out the Biodiversity status of fishes in Vattakkayal of Kollam district, South India. Fishes were collected from the study area and the Meristic and Morphometric characters were measured and fishes were identified up to the species level, with the help of standard keys given by Day (1967), Jayaram (1999), Talwar and Jhingran (1991). Conservation status of fishes from the Vattakkayal was assessed by following the CAMP and IUCN conservation status. The survey of the studied stretch of river resulted in recording of of 22 fish species belonging to 10 orders and 17 families. IUCN (2011) and CAMP (1988) conservation status of each fish was listed. It was found that out of 22 species reported in the present study, 13.63 % are Vulnerable, 4.54 % are Endangered, 4.54 % are at Lower Risk And Near Threatened, 27.27 % are at Lower Risk and Least Concern,31.81% are Least Concern, 4.54% are Critically Endangered, Data Deficient for 4.54 % species and 9.0 % are Not Evaluated as per IUCN Red list category (2011). As per CAMP (1998) evaluation status, 9.09 % species are Critically Endangered, 36.36 % are Vulnerable, 4.54 % are at Lower Risk And Near Threatened, 4.54 % are at Lower Risk, 9.09 % are data deficient 36.36 % are not evaluated. This is a pioneer study on the fish diversity of Vattakkayal, a part of Ashtamudi lake and would help in adding some additional species to the previous diversity studies conducted on the diversity of fishes in the water bodies of Kollam district,South India.