The best time to clean ponds is in late autumn when many creatures are less active.

Pond cleaning

• Start by preparing a holding tank in a shady spot for fish and deep water plants; use some pond water in the tank, unless it is particularly cloudy. Marginal (water’s edge) plants will survive out of the pond as long as they are kept moist and shaded
  
  
• The easiest way to drain the pond is to use a pump, which can be rented for the day from a machinery hire shop
  
  
• As the water level falls, remove fish as they become visible
  
  
• Remove plants as the water levels drops, placing them in the holding tank. Take the opportunity to re-pot or divide plants if necessary
  
  
• If you find any, put larger pond creatures into the holding tanks
  
  
• Place decaying plant material on the side of the pond, so any smaller creatures hidden away can return to the pond
  
  
• Scoop up the silt from the base. You can use this on your border, but retain a little to add back to the pond as it will help re-establish tiny organisms
  
  
• Clean the liner with a scrubbing brush and water, bailing the dirty water out with a bucket
  
  
• Return the saved silt and any saved pond water. Next, refill with water (rain water if possible), positioning pond plants as you go
  
  
• Finish by returning the fish and any other creatures. After cleaning out the pond, it can take several months or years to return to a balanced ecosystem