Not only is the growth of algae in a fish pond unsightly, it can also be detrimental to the health of the fish living in the pond. Cleaning a fish pond can be done anytime that algae starts to get out of hand, but generally needs to be done only once a year to keep the pond clean and clear of algae.
Clean a fish pond early in the spring before the water temperature has reached 55 degrees Fahrenheit. If cleaned after this temperature, bacteria that is good for the ecosystem will have already begun to form and it will be destroyed, which will be harmful to life in the pond.
Do the entire cleaning process in one day. Fish should be left in a holding container in the sun for no more than a few hours.
Drain the pond using a sump pump or skimmer pump and its piping attachment until there is only 6 inches of water left. Cover the opening of the piping attachment with chicken wire or a screen to keep pond life from being pulled into the pump.
Remove the fish from the pond with a fishnet. Place them in water in a holding container while the pond is cleaned. Cover the container if you have frogs or koi fish to keep them from jumping out of the container.
Spray the rocks and pebbles lining the pond with a high-pressure water hose, moving from top to bottom. Turn on the pump while spraying the rocks so that debris removed from the rocks will be sucked out. When the water flowing into the pump becomes clear, the loose debris has all been removed.
Pull out and hose off the pond's filter. Continue to rinse the filter until the water runs clear.
Replace all of the pond's components except for the fish and other living plant life, then begin refilling your pond with the pump. Pour in a chloramine buster if you are using city water to counteract the chlorine in the water. The amount that should be added depends upon the size of your pond and will be listed on the bottle.
Return the fish and other pond life to the pond when it is half full. Use buckets to transfer the fish to the pond. Lower the bucket into the water and keep the bucket resting in the water for approximately 15 minutes. The water will gradually become the same temperature inside and outside the bucket and the fish can be released.