hi guys need some advice on a future tank (already have option to buy) so the tanks a 7x3x3 i already own a 6x2x2 will be using this as the sump i understand i can keep some smaller cat sharks in here possibly just a species aquariam with say a marbled cat shark can anyone give me advice in general on equipment and decor say live rock no live rock and any other bits i may need to know or need for the tank thanks.