Will fish in a lake die if the pH drops below 7?

Fish can be affected by a drop in pH below 7, as many species thrive in a more neutral to slightly alkaline range (around 6.5 to 9). A significant decrease in pH can lead to increased toxicity of certain substances, disrupt the fish's physiological processes, and harm their gill function. While not all fish will die immediately, prolonged exposure to acidic conditions can be detrimental to their health and survival.