The ornamental design for a “modular floating dock fender,” as shown and described.
FIG. 1 is a reduced perspective view of a modular floating dock fender, showing my new design from the front, top and left side, wherein a portion of a floating modular dock is shown in phantom as forming no part of the claimed design;
FIG. 2 is a front side elevational view of the modular floating dock fender;
FIG. 3 is a top plan view thereof;
FIG. 4 is a bottom plan view thereof;
FIG. 5 is a left side elevational view;
FIG. 6 is a right side elevational view thereof; and,
FIG. 7 is a rear side elevational side view thereof.