Top up ponds and water features if necessary - a spray attachment on the hose will aerate the water, and help the fish.
Any pumps on water features should be left on during sultry nights, as oxygen levels are lower in such conditions.
The fully developed larvae of damselflies and dragonflies emerge from the water by climbing up plant stems where they shed their skins to transform into the flying adults. Add upright marginals such as water iris if your pond lacks suitable plants.
Remove dead foliage and blooms from waterlilies and other aquatic plants. Continue to skim blanket and floating weeds.
Cover ponds with nets or safety grills in gardens where young children play. These have the additional advantage of preventing leaves falling into the pond.