Day after the Tribune highlighted dead fish in the Sukhna lake, the Department of the Animal Husbandry and Fisheries, has sent its samples to the Zoology Department of the Panjab University (PU) on Monday. Joint director, Department of the Animal Husbandry and Fisheries, Dr Kanwarjeet Singh, said teams of the department had collected samples, which were sent for further investigation to the Zoology Department of the PU. More than 15 fish were found dead at the Sukhna lake on Sunday. Lack of oxygen in water seems to be the primary reason for the death of the fish. However, we have sent samples to the PU to know about the exact cause of the death, said Dr Kanwarjeet.