The ornamental design for a fueltankfloat, as shown and described.
FIG. 1 is an isometric view of the fuel tank float.
FIG. 2 is a front elevational view of the fuel tank float, the rear elevational view, left side elevational view, and right side elevational view each being identical thereto; and,
FIG. 3 is a top plan view thereof, the bottom plan view being identical thereto.