African Dwarf Frog ~ Best Filter

Okay I have just recently purchased a 2.5 gallon tank and I want to get two African Dwarf Frogs for the tank, however the tank came with a whisper filter (waterfall type), the thing is it's huge takes up way too much room in the tank, any suggestions on a hanging type filter that is smaller and effective? Or what type of filter should I use to help keep the tank clean?

Use the one that you have. It may look big but that is only because your tank is so tiny. The small whisper filter is actually pretty decent. If you are really set on getting a new one, get the Hagen Aquaclear 10. It will do a good job, and you can adjust the flow so you won't have to worry about your frogs getting sucked up the intake.