Excess nutrients, warmer temperatures, or other factors can cause algae blooms, which may have a negative impact on fish and their food sources. 

At first, algae blooms alter aquatic insect habitat, which may increase the rate of some insect hatches while decreasing others. In addition, algae blooms are unsightly and can be a nuisance when swimming or fishing.

Finally, severe algae blooms can lead to additional plant biomass in the ecosystem that must be broken down by microorganisms. When bacteria decompose the extra plant matter, they consume oxygen dissolved in water that fish and aquatic insects need to survive.