Generally when moving fish from one pH value to another, it's the sudden change in total dissolved solids (TDS) that causes issues such as osmotic shock, not the shift in pH. Going from high TDS values to low TDS values is far more stressful on most fish, vs going from low to high.
So for some fish, especially newly imported wild caught specimens, a sudden change in water values can become a double whammy. Initial stress from a sudden change in TDS that triggers osmotic stress, followed by an onslaught of bacteria that are not typically found in their native habitat.
So for some fish, especially newly imported wild caught specimens, a sudden change in water values can become a double whammy. Initial stress from a sudden change in TDS that triggers osmotic stress, followed by an onslaught of bacteria that are not typically found in their native habitat.
