What's the best Internal Filter???

[codeoverride]

I have a 10 gallon tank and no room in the back for one of those outside filters (unless you guys can point me to one that I can hang on the side of the tank - I'm also still looking for a lid/light so I'd really appreciate any ideas to make that work).

My question is what's the best internal filter for a 10 gallon tank that is not ridiculously expensive?

Thanks so much!!!

 

[gheitman]

I use sponge filters on all of my 10 and 20 gallon tanks. The advantages are (in no particular order):

low cost
easy maintenance (just gently squeeze the sponge in tank water once every week or two)
great biological filter (no chemical filtration so it won't have an effect on any medications)
mechanically reliable
provides feeding surface for small fish

They aren't the prettiest but you can hide them behind some driftwood or plants.