ACUTE TOXICITY OF METAL CYANIDES TO INDIAN MAJOR CARP Labeo rohita (HAMILTON)

Static renewal bioassay tests were carried out to determine the acute toxicity (LC50) of metal cyanides to the Indian major carp Labeo rohita. The 96 hour LC50 value for the sodium cyanide, zinc cyanide and copper cyanide to the fish L. rohita were 0.32 mg/L 0.35 mg/L, and 1.1 mg/L respectively. Among the metal cyanide tested, sodium cyanide is found to be more toxic than the other cyanide complexes. In general behavioral responses of the fishes exposed to cyanide included uncontrolled swimming, erratic movements, loss of balance, moving spiral fashion with sudden jerky movements, vertical movements lying on the sides of the test chamber and rapid flapping of the opercular movements with opened mouth finally settles to the bottom