06/12/2026
U. G. Ander says, "Algae is needed in fish ponds. But some algae blooms can make ponds unsightly, while others can make ponds dangerous!"
Algae are important in ponds, providing a vital link in the food chain. But certain species can cause harmful algal blooms (HABs) that produce toxins, turning the water green, blue-green, or red and producing surface scum or foam. If HAB is suspected, keep people and animals away and avoid using the water for irrigation. UGA Extension offers water tests for algae and toxins; contact your local agent. To prevent blooms, reduce fertilizer runoff by limiting fertilizer, adding buffer strips, and keeping animals out. Use aerators sparingly to prevent stagnant water.