The top must be above the water enough so that the water has enough room to have a little waterfall. This is part of what adds the oxygen to the water. It doesn't need to fall much more than 1/2" or so but more is better if you can manage it. Good luck with the aquarium. Whisper filters are good and they keep your water clear, but don't change the filter media too often.
I hate my Whisper filter. It works fine but first they recommend that you replace the filter every month. $$$$$ No need to if you rinse it well in tank water. However, the filter then looks terrible. The flow is fine and it all still works, but I will replace the whole thing when the flow is restricted. Bring me another AquaClear, please! ;D
AMEN Dahly!!!! I have 1 big whisper and 3 smaller ones and I absolutely hate them. Am slowly replacing everything with Aquaclears. I just can't reconcile buying new filters as long as the old ones still work :'(
I use the power filters. The filters aren't too expensive (the blue charcoal ones with the fiber bio thing). I like the noise they make. That's part of the reason I own an aquarium. I find it soothing like a trickling brook. I don't use any aeration except this. I hate those noisy little pumps that I try to weight down with bolts ect so they don't float to the top. And they always vibrate and make annoying noises and sometimes will walk off the table by themselves.
A looooong time ago (when I didnt know anything about fish and just rinsed the entire tank in tap water 1ce a week I wondered why the fish all died so often, once I put a betta in there and he died in 2 days no heater :'( :'( sorry chickadee)
I had 2 goldfish in a 1 or 2 gallon hex tank with a aerator and it made a nice noise like my filter, all bubbly