Not sure but I would put two airstones, one in the tank and another in the canister filter to keep the oxygen levels up. Fishes should definitely survive with the airstones, not sure about the BB. Also, don't feed the fish or feed very little so that there's no additional ammonia load in the tank. I have been there, done that during long power failures. Didn't see any ammonia or nitrite spike later.RookieTank said:My gasket seal broke on a fluval 406 and is going to arrive on Sunday. Can material and fish survive two days with no filtration?