Well, rocks ans plants make the tank look more natural, and that's how i like it! But more inportant, rocks, plants, etc. create good hiding places for the fish in your tank and thus they will feel more safe and will behave more natural. Also, they most often show much better colors.
I believe creating a natural environment is even more important than the gallons of water u lose while adding rocks and plants... And last but not least you can increase the amount of fish load of most tanks by upgrading the tanks filter.
Last edited by Ajsim; 07-24-2009 at 02:13 PM.