There are products available to control mosquitoes in the pond. Mosquito dunks or floating Bt briquettes control mosquito larvae and do not harm fish. One briquette last about 30 days and treats 100 square feet of surface water. You can find them in pet stores or stores that sell pond supplies. Clean and chlorinate swimming pools that are not in use.
Mosquitoes can breed in the water that collects on swimming pool covers.
Use landscaping to eliminate standing water that collects on your property. Mosquitoes can breed in any puddle that lasts more than four days. You may want to fill tree stumps with sand to prevent pools of water from forming in them. Clean livestock-watering troughs monthly. Also keeping vegetation trimmed low can eliminate resting sites for mosquitoes in the daytime.