Following the announcement of the deaths of fish stocked in the human - made wetland in the Parak Village located on the Chabahar - Konarak route by the head of the Negour Department of Fisheries and the expert of the Veterinary Directorate General of Chabahar, Dr. Ajdari, the head of the Chabahar Offshore Fisheries Research Center, along with the head of the aquaculture department visited the site, inspected the area and sampled dead fish and water. A field study of the pattern of casualties did not show infectious disease. After transferring the samples to the research center, the gills, skin and intestines of the fish in terms of parasitic infection were examined in the laboratory of aquatic animal health and diseases of the Chabahar Offshore Fisheries Research Center. Eukaryotic parasites and prokaryotic parasites were not observed. Also, the study of environmental conditions indicated that the catchment area was about 15 hectares with a depth of 1 to 4 meters. Severe plankton bloom was observed in the human - made wetland. According to the farmer, the bighead carp, grass carp and common carp were stocked in the human - made wetland. The silver carp, which feeds on phytoplankton, has not been stocked. Therefore, this lack of observance of the proper species composition among carps is the cause of fish mortality. It was suggested that, if possible, a number of silver carp be added to observe the species composition. Also, it was recommended to the farm manager to check the environmental status of water and wetland bed in terms of dissolved oxygen, pH and TOM.