As fish are totally dependent upon water to breathe, feed and grow, excrete wastes, maintain a salt balance, and reproduce, understanding the physical and chemical qualities of water is critical to successful aquaculture.

To a great extent water determines the success or failure of an aquaculture operation.

Very high (greater than 9.5) or very low (less than 4.5) pH values are unsuitable for most aquatic organisms.

Young fish and immature stages of aquatic insects are extremely sensitive to pH levels below 5 and may die at these low pH values.

High pH levels (9-14) can harm fish by denaturing cellular membranes.

Changes in pH can also affect aquatic life indirectly by altering other aspects of water chemistry. Low pH levels accelerate the release of metals from rocks or sediments in the stream. These metals can affect a fish’s metabolism and the fish’s ability to take water in.