A few hours ago the venturi device on my filter stopped working, This has always gave the bubbles to my tank, which ive always assumed is the oxygen getting to the tank, so with the bubbles no coming no more, i have the output part on the filter to point upwards and greatly agitate the surface, I have ordered a air pump, but it wont arrive til wednesday, so will this be ok for my fish and they wont starve of oxygen? i would greatly appreciate some advice as I dont want to lose any of my fish, thanks.