Substrate leveling fish (other than Corys)?
When I had a 20gal, I enjoyed keeping cory cats, and their behavior of sifting through the substrate would tend to keep it nice and level. That's kinda finicky for a "natural" aquascape perhaps, but I liked it.
So with a nano (~5gal) tank, where the cory cats are probably not a good idea, is there any other fish/invert that would have a similar effect? I was thinking ottos, but I'm not sure how much of an impact they'd have since they tend to spend a lot of time on the glass.