Hi, air pumps aren't a strict necessity, does your filter give good surface movement? Most oxygen is dissolved into the water through surface agitation.
It also has to do with how many openings you have in your tank cover. My canister filter agitates my water surface like crazy. But I noticed all my fish one day at the surface of the water as if gasping for air. My canister filter was running but I accidentally unplugged their airstones. The air between the water surface and the lid was running out if oxygen. I plugged the air pump back in and left the lid open for an hour and the fish returned to their normal swimming routine.
Just watch the fish. If they gather at the corner of the tank like a bunch of teenagers at prom trying to get air, it’s time to look at getting an air stone or try to create more agitation.
It also has to do with how many openings you have in your tank cover. My canister filter agitates my water surface like crazy. But I noticed all my fish one day at the surface of the water as if gasping for air. My canister filter was running but I accidentally unplugged their airstones. The air between the water surface and the lid was running out if oxygen. I plugged the air pump back in and left the lid open for an hour and the fish returned to their normal swimming routine.
My only concern is you keep oxygen filled air between the water surface and the lid of the tank. You can use an air pump with the hose and no air stones at all. You don't have to have the hose in the water at all if you already have agitation at your water surface from your filter. If you don't have adequate fresh air getting to the water surface, you can just have the air hose just inside the tanks lid or cover blowing air. It would work just as well.
