i think the size of the rock has to depend on the size of the tank
one ten pound rock isnt going to look as good to me in a nano as a few smaller pieces equaling the same weight, and a larger tank, to me, looks better with larger rocks.
my taste also runs towards rocks with a lot of holes and crevices rather then the flatter or branching styles.
You should look through the members galleries, see which tanks you like and see what they have and try to go about it that way
"I know the human being and fish can coexist peacefully."
â€”Saginaw, Mich., Sept. 29, 2000