Internal capacity of the C is about 11,900lbs. Internal capacity of the E is 14,400lbs and the F is in the 13,100 range IIRC. Usually the E/F's will fly with one 480 gallon drop tank adding another 3,264lbs. of fuel. Increasing total fuel to 17,664lbs.
The F-15E carries (Internally) 13,700lbs or so. Although apparently they usually fly with Conformal Fuel Tanks so that ups the fuel to 22,630lbs.
These numbers are with JP-5