Mosquito larvae (mainly Culex spec., but there are new genera invading the western hemisphere now in the course of climate change) are since long known as very good food for our fish if not too big (as Helene told in the opening mail). The special quality is seen by the fact that this food leads the females to develop a good stock of eggs (which is nearly impossibe with Daphnia spec., for instance). And the tiny forms that come out of the rafts are since long known as a very good food for raising our offspring.
Malaria mosquitos (Anopheles spec.) look very similar and obviously spread to formerly colder climate ranges, too. They have been found recently quite often in Germany among Culex where they were totally absent in former times. They are readily taken by our fish, too. Up to now, a danger of getting infected with Malaria in our countries has not been reported.
There are two things that are not widely known. The first (that was even new to me) is the knowledge of our experienced friend Bernd Bussler (from Hamburg) that you can find them even in Winter at special places. Bernd is a hard-working catcher of live outdoor food even when most ponds are frozen; and his success with breeding all Parosphromenus is widely recognized and acclaimed. The other thing is that you could store the rafts in the refrigerator for quite a long time without water. If placed at the water surface of an aquarium they will soon hatch and produce that tiny food that was spoken about. By this means you can store quite a mass of rafts in the autumn and use it in winter for your offspring.