I like a mix of black sand and PFS. I like the look of it with a few scattered pebbles and stones. I just set up my 6-year old son's first aquarium (proud dad is smiling). It is a 10 gallon with a Marbled Cray and a few Tetras. He knows that the Marbled Cray is intended to make feeders for dad's tanks and he's cool with it. As long as he can keep at least one Cray for himself at all times he is fine. The other condition was that his first tank have a complete Sponge Bob theme (dad grits and bears it). I'm just happy my son has taken a plunge into the hobby. I'm proud to announce that the Marbled Cray has taken residence in the Krusty Krab.
Hey, for a six year old I totally get the silly decoration thing. Now, tanks decorated like a tank for a six year old but owned by a grown man with no children? Don't know about that.