author(s)
Asim Ullah, Hameed Ur Rehman, Sajid Awais, Muhammad Ahsan Sardar, Abdul Maalik, Noor Muhammad, Shehzad Zareen, Muhammad Ateeq, Raqeebullah, Waqar Ahmad, Feroz Khan and Kausar Saeed

abstract
The present investigation is about to determine the acute toxicity and 96-Hr LC₅₀ value of Cu for the fish Oreochromis niloticus. The fish were exposed in aquaria to different concentration of metal and the concentration of metal was increased gradually for 96 hours to investigate the response of the fish. With the increase of the concentration of metal the response of the fish mortality were increased gradually. The result showed that LC₅₀ of copper sulphate for the fish, Oreochromis niloticus is 30 mg/l. The mortality of the fish is directly proportional to the concentration of the exposed metals.