with these tanks, it appears that the water level is intended to reach the maximum height of the tank...or at least, one is *able* to fill it that full. Anyone else who owns one of these tanks will know what I mean... However, this leaves very little of the surface area exposed to actual air. So, excluding those fishes that breath atmospheric air, should I consider this room for exchange of gases a crucial thing? ((haven't put any fish in yet, so don't hurt me please)) 
