Why isnt air coming out of tube ..

Brief：
I just changed the water in our 1 gallon tank. I hooked the air pump back up and it is blowing air and running fine, but there are no bubbles coming o.. 

I just changed the water in our 1 gallon tank. I hooked the air pump back up and it is blowing air and running fine, but there are no bubbles coming out of the tube inside the tank. What could be wrong? Help.I don't want to kill the fish!

Relax fish are really pretty tough.

Try removing the air stone and cleaning it with a clean new toothbrush. Look closely at the tubing, You may have an air leak.

Cut off the first inch or two and replace airstone , see if this helps.

If all else fails remove tubing from aeriating device and weigh it down in the tank without stopping the air flow, and get a new air stone. take out the tube and blow into it to be sure it isn;t kinkd or clogged.If so, fix that.

Could be the pump needs fixing. There is a screw by the outlet of air that adjusts the flow. It may need adjusting with a phillips screwdriver.

COuld be the pump gasket that pushes the air is rotton or torn. It could be fixed with glue, but temporary. Usually the pet store seells a replacment or get a new pump. Those little air pumps don't last forever.Even if its blowing air ,it may not be enough pressure to blow air into the water.Buy another pump,(they're not that much). Check the air tubing to be sure that it is not kinked (bent sharply) and preventing the air from getting through. The air coming out of the pump is used to stir up the surface to help the water get rid of carbon dioxide. The rule is one inch of fish per gallon of water in fresh water tanks one inch of fish in five gallons of water in salt water tanks for them to survive. Check the pump first to see if air is coming out of it. Then check the tube if you have a back flow protector make sure that is on the right direction if it is going through the tube and the pump is putting out air then check the attachments to see if they are blocked or clogged. If the tube is very long or kinked the pump may not be able to push out air. Make sure the tube is attached tightly to the pumps no loose air escape places as the force of the air will go out the areas of least resistance. That is the extent of my experience with problems also check to see if anything is sitting on the tube like the top of the tank or glass on the top of the tank. You may have a hole in the tube at another place, not in the water -- the air could be escaping that way.

Is the tube bent anywhere? A kink would block the air flow.

The pump is plugged in? Maybe theres a hole in the tube? at a guess you need a new air stone ,they do stop working sometimes. dont worry about the fish,you dont have to rush out and buy a new one as they will be OK for a while.