Recovery facilitation of malathion-intoxicated freshwater fish by exposure to hypertonic environment

The possibility of recovery in a hypertonic environment (10-40%NaCl) was investigated in the freshwater fish Oreochromis niloticus acutely intoxicated with the pesticide Malathion (40 ml/l. Survival was significantly higher in 15 g/l NaCl, with a shorter time required to reover posture and swimming, although 20% of revovered animals died on subsequent days.Exposure to a hypertonic environment plus pesticide did not protect the animals. Fish explosed to air until they became unresponsive recovered faster in freshwater than in a hupertnic environment. It os concluded that a hypertonic environmnet only facilitates recovery and that although osmotic mechanisms may explain the results, other possibilities reamin to be investigated