Add a fountain or waterfall to move water around your pond. Mosquitoes need still water to lay their eggs; they avoid water that is constantly moving.
Treat your pond with Bacillus thuringiensis israelensis, called Bti, or methoprene. These chemicals are the primary ingredients in "mosquito dunks" and kill any mosquito larvae. They are safe for fish, pets, waterfowl and people when used as directed.
Remove any excess organic material from your pond such as leaves or grass. This material provides food for mosquito larvae and can shelter them from natural predators.
Fill in any small "pools" of water between larger rocks with gravel. These pools provide still water for mosquitoes to lay their eggs and safety from any fish living in your pond.
Place bat, purple martin and duck houses around your pond. Bats and some species of birds such as martins and waterfowl feed on mosquitoes and will be more likely to feed around your pond if they have a safe place to roost.
Add top-feeding minnows, mosquito fish (Gambusia affinis), goldfish or guppies to eat the mosquito larvae. Don't add mosquito fish to ponds that are connected to other natural waterways because they can disturb the natural balance and take away resources from native species.
Remove any sloping edges in your pond by raising the water or scooping out the sides. Ponds with sloping edges provide water deep enough for mosquito larvae to travel but too shallow for any fish that might prey on them. Periodically raise and lower the water level in your pond to reduce or drain any shallow areas.
Do not overfeed fish in your pond. Fish that are not hungry won't eat the mosquito larvae.
Thin out any dense growths of aquatic plants. Dense growths of aquatic plants provide sanctuary for mosquito larvae. Thinning them out allows fish and water to circulate easier.
Add shade trees around your pond. Small ponds can heat up in the summer, which reduces oxygen and kills the fish in your pond. Providing them with shade helps keep the water cool.