We have a pond it is quite large it has trees around the edge, our fosse filter bed drains in to it (the water coming from the filter bed has been tested and is drinkable, although I won't be the one to try it) we have carp and some other fish in it, some quite large, at certain times of the year it will turn green with algae but clears after a few days, if it becomes a problem you can throw a small bale of barley straw in to clear the algae. the fish eat most of the mosquito larva, I wont say we don't have mosquitoes but they are usually about before 10am and after 4pm so your fairly safe between these times. Our pond is a very attractive part of our property we have a bench by it and love to take some stale bread to feed the fish and the wild ducks, and keep an eye open for all sorts of wild life, dragonflies, newts, frogs, toads, butterflies, pond skaters are just a few of species that live in and around the pond, we have spotted a kingfisher checking out the pond,and even had a stag come for drink of water while we sat there, really magical moments, no two days are the same the sunlight and shadows on the water and the wind all have an affect on the appearance of the pond. You haven't said what size your pond is,I assume it is large as your fosse filter bed drains into it, but if it is smaller garden pond size then maybe you need to add a pump a filter some plants and of course some fish to eat the mosquito larva. what every you decide good luck with it.
