The ornamental design for a swim fin having shortened distal portion, as shown and described.
FIG. 1 . Is a top front perspective view of my swim fin having shortened distal portion with the phantom line showing being for illustrative purposes only;
FIG. 2 . Is a right side elevational view thereof, the left side elevational view being a mirror image that shown;
FIG. 3 . Is a front elevational view thereof;
FIG. 4 . Is a rear elevational view thereof; and,
FIG. 5 . Is a top plan view thereof, the bottom plan view being a mirror image that shown.