10 hints for maintaining your garden's pond

Ponds make a great addition to the garden, but there are few regular maintenance items you'll need to add to your outdoor chore list.

• Wait two weeks after filling your pond to add plants and another week to add fish.

That way, neither plants nor fish will be harmed by possible chemical contaminants in the water.

• Limit algae by growing plants, such as water lilies; they block the sun that algae need for growth.
• Also include rooted floating plants, which provide food for fish and help oxygenate the water.

Beautiful koi are great for large ponds, but they're too active to adapt to very small ones.

• Plain comet goldfish withstand cold weather well and are good at hiding from predators.

Don't just plunk your fish into the pond.

• Let them adjust to their new surroundings by floating the unopened plastic bag containing the fish on the pond for one hour; then open it gently and set the fish free.

Each fish needs a certain quantity of water to live.

• Calculate the required minimum by multiplying the Imperial measured length of the fish by five: a four-inch (10-centimetre) goldfish, for example, needs at least 20 gallons (76 litres) of water.
• Another easy way to gauge space is to allow one square foot (0.09 square metres) of pond surface area per inch (25 millimetres) of fish.

Remember, too much water is better than too many fish!

• Encourage fish to eat insects — especially mosquito eggs and larvae — by letting them fend for themselves in summer.

In spring and fall, feed them as long as the temperature is above 10°C (50°F). In winter, don't feed them at all.

Never overfeed; excess food in the water upsets the pond's balance and can encourage algae.

Frozen water expands and puts pressure on the pond sides.

• In late fall, weight the necks of sealed, empty plastic bottles with stones tied to strings and place the bottles in the water.
• The ice will press on these flexible air pockets instead of the liner.
• You can also use rubber balls or floating logs.

• Despite their nighttime croaking, frogs and toads are welcome additions to the pond; they eat insects and are entertaining to watch.

But don't let the population get out of control: tadpoles feed on aquatic plants. Keep their numbers in check by scooping the frogs' clear, jellylike eggs out of the water each spring.

Fish become semi-dormant in winter, but they still must breathe. If the pond surface freezes for weeks, toxic gases in the water can build to harmful levels.

• Make a vent in the ice by heating a pot of water and setting it on top, repeating as needed.
• You can also buy an electric de-icer, which ensures an opening in the ice at all times.

• If aphids attack your plants, place plastic mesh over the leaves to sink them into the water; fish will find the pests an unexpected treat.
• After the leaves have been nibbled clean, remove the mesh.