This is the little bubbler we used. It is important to
add oxygen to the water especially for the tilapia. We
leave this on all the time and have added a stone on the
end to create smaller bubbles.
We have suspended it off the sides of the tank so the vibration does not annoy the fish as sound travels very well in water.
The ideal range of dissolved oxygen concentration in the water should be about 3 ppm (parts per million) though for Tilapia less ppm is not considered lethal.