I live in the desert and have a population of Gambusia fish that only get to a couple of inches long and control the mosquitos nicely. We also have dragonflys, wasps, and other insects that are always around the pond. I don't know how it is there but I would guess it's pretty warm and humid (depending on where in Italy). Running water that breaks up the surface might be the easiest method. Good luck. I don't think you'll regret having a pond, it can be a very serene place to relax.
