I wonder, if anybody who writes in these forums have read the many informations on our fish advertised in the left of our frontpage.
Basic information is given there. Paros are – in spite of having a well-functioning labyrinth – nor surface fish. But normally they don’t use it for breathing. Therefore they normally live in greater depths and have no special relationship to the water surface. That means: Drosophila is not a suitable food for them.