Test your pond water for pH balance, which is the measure of the acidity or alkalinity of a liquid. The best pH level for fish to survive in water is between 7.5 and 8. This is also the level that most plants find sustainable. If the pH level is low, you add limestone chips to the pond to raise the pH level. If the pH level is too high, sprinkle calcium carbonate to keep it at the desirable level. Check this pH level every week to make sure it stays between 7.5 and 8.
Clear your pond of decaying or diseased plants or materials to maintain its cleanliness. For debris at or near the pond edges, use your hands or a shovel to remove these dead materials. For debris and wild plants or grass growing in the middle of the pond, use a pond rake to capture unwanted materials. Attach the rope to the free handle of the rake, throw the rake into the center of the pond and slowly pull the rake back to the pond shore. Gather materials into a trash bag. Repeat until all debris is cleared.
Add water conditioning treatment to the pond to prevent algae from growing and protect whatever life is in the water. A general rule for mixing is 1 quart of conditioner for every 1000 square meters of pond area. Most garden ponds measure less and will therefore need less than one quart.
Limit the fish you allow in the pond. A suggested ratio is one fish for every 10 gallons of pond water. The lesser the ratio, the better it is for the fish and other aquatic life.
Check your water level every week, especially in the dry season. You may need to add water, if necessary, to keep the water level to the maximum and provide sufficient oxygen for your aquatic life to survive.