I'VE JUST SET UP A NEW TANK ABOUT 2 MONTHS AGO AND HAVING RECENTLY ADDED MY ANGEL FISH I'VE FOUND THAT THE FEMALES APPEAR TO GASPING FOR AIR ON THE SURFACE BUT THE MALE LOOKS HAPPY ENOUGH.THE TANK THAT I'VE SET UP IS A VISION 260 WITH JUST THE STANDARD H FILTER IN IT.COULD THIS JUST BE A CASE...