I have a 55 gallon tank set up with no live plants and 3 red belly piranhas and I am running a Magnum 350 canister filter. My question is about whether I can not run an air pump with this setup. I just moved the tank close to my room and the air pump is louder then I care for. I have tried to move it and reaarange it but it is not help. Would not running an air pump be bad or does the 350 cause enough surface disruption and water moving to maintain? I did some looking online and have read that contrary to what I believed true, the air pump does not add oxygen to the water it only causes surface disruption and helps move the water around, and is not necessary if you have a large enough canister moving the water. Anyone have any ideas???