How Much Salt Can Freshwater Fish Tolerate?

How Much Salt Can Freshwater Fish Tolerate? Peter told us: “For counteracting the effects of high nitrite, just 100 mg (0.1g) salt per litre is enough. This very low salt level is tolerated by virtually all freshwater fish, even catfishes.” What freshwater fish are sensitive to salt? The Corydoras catfish are particularly sensitive to salt;