How to Get Rid of Algae in Fish Ponds

The term "algae" is used to describe many photosynthetic organisms that live in water sources including ponds. Algae range from small spores, to clumps of material that look like plants, to what looks like scum clinging to the surface of the water, rocks or plants, to seaweed. The right amount of algae provide water-life with oxygen and food. Too much algae, however, and a fish pond can be overrun. It may look like pea soup and the life in the pond choked out. Removing excess algae is vital to maintaining a pond's health.

Things You'll Need

  • Holding tanks
  • Scraper
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Instructions

  1. Removing an Infestation

    • 1

      Drain the pond and store your fish. If an algae bloom is bad enough, the best bet is to empty the pond and start fresh. Put fish, with water from the pond, into holding tanks while the pond drains.

    • 2

      Kill and remove any string algae. String algae looks like green hair and typically grows at the bottom of ponds where the water is more still. Pour kosher or other non-iodized salt on the algae and let it sit for about three days before removing the algae.

    • 3

      Clean other surfaces. Rocks, artificial plants and the pond's walls may be harboring plankton--the other most common type of pond algae. Plankton will look like a green, mushy scum all over the items in the pond. This is also the algae that, when floating freely in the water, makes the water look green. Use a scraper with a sponge on one end to wipe down all the surfaces in the pond. Clean rocks, the pond's sides and any ornamentation you have in the pond.

    • 4

      Refill the pond and return the fish. Use clean water with its proper treatments to refill the pond. Re-introduce your fish to the now-clean environment.

    Prevent Another Infestation/Knock Back a Small Infestation

    • 5

      Reduce fish feeding. Extra food that goes uneaten by fish provides extra fuel for algae. If you see that your fish are not eating all their food, give them less so that new algae is starved and cannot grow.

    • 6

      Reduce the amount of sunlight that gets into the pond. Algae need the sun's light to grow. Installing trees around the pool or shady decorations like large leafy plants will prevent light from getting to budding algae and will also look great.

    • 7

      Remove dead, dying or decaying plants in the pond. Plants at the end of their life cycle will give algae extra food to grow. Keeping your pond clean will reduce the amount of algae that can survive.

    • 8

      Install an aerator. A well-functioning aerator will keep plenty of oxygen in your fish pond and prevent algae from growing in stagnant water.