To give you the exact figures...
The aircraft has eleven fuel tanks, two surge tanks and three vent tanks. Five tanks in each wing (outer, outboard feed, inner, mid and inboard feed) and one tank in the horizontal stabilizer, named the ‘Trim Tank’. In each feed tank is a dedicated engine feed collector cell.
Each wing also contains a surge tank and a vent tank. A vent/surge tank is located in the right hand side of the horizontal stabilizer.
The center tank installation is optional for the A380-800F and standard for the A380-900. (Yes they will be built !)
When the center tank is not installed the total usable fuel volume is 315,354 liters. With the center tank installed the total usable fuel volume is 357,054 liters.