Welcome Pam
I researched the question and found a lot of comments that state the mosquito dunks are safe for bees. Some also said if the water is refreshed every few days mosquitoes won't lay their eggs in it. They need still water for 10 days to hatch.
I would think if your pond water is circulated through a pump or is topped up with fresh water every so often you shouldn't have to use the dunks at all.
