How to Remove Algae from a Fish Pond

Removal

• 1

  Remove the fish from the pond. Place the fish in holding containers, along with water from the pond. Do not attempt to introduce them to fresh water at this point.

• 2

  Drain the pond. If the algae infestation is significant your best bet is to simply remove all of the water and start over. If that is impossible, then remove as much of the algae as possible, and repeat in a week or two if necessary.

• 3

  Remove any remaining string algae. There are two basic types of algae -- string and plankton. The plankton algae floats in the water and causes it to turn green and murky. The plankton algae should drain out with the water. String algae, as the name implies, looks like green strings and tends to live on the sides or bottom of the pond. After you drain the water, pour non-iodized salt into the pond, leave it there for two to three days, then remove any remaining string algae by hand.

• 4

  Clean the pond thoroughly after you have removed the algae. Wash down any rocks, scrub the walls, and remove any debris, such as leaves or dirt.

• 5

  Replace the water with normal tap water. Return the fish to the pond.

Prevention

• 6

  Limit the amount of sunlight the pond gets, as algae thrive in warm, sunny conditions. While it may be too late to change the initial design of the pond, you can use plants to help eliminate sunlight.

• 7

  Control the nutrients in the pond. Algae need nutrients to survive, so by eliminating access to nutrients you will help prevent algae growth. Try to prevent rainwater from entering the pond, as rainwater has bacteria in it that the algae can use. Make sure the fish eat all the food you give them, or skim out anything they do not eat.

• 8

  Clean your filter regularly. Your filter can become clogged with leaves and debris that then break down and become nutrients for the algae. In addition, if the filter is clogged it can prevent the beneficial bacteria that live there from surviving.

• 9

  Use algicides. There are a number of chemical products that you can add to the pond water to help prevent algae growth. Be careful doing this, as algicides can have a negative effect on some aquatic plants and animals.