What makes a fishtank look natural?

[Dwarfs]

This makes a tank look natural. Badly planted plants, randomly placed rocks, and natural gravel

 

[pendragon]

Ken, that's a nice tank! But I'm curious - what did you use for the "leaves" lying on the substrate? I'm assuming those aren't real, else they'd decompose? They're a nice touch, though!

pendragon!