The ornamental design for a containerassemblymountable on a fishing rod, as shown and described.
FIG. 1 is an exploded perspective view of the container assembly mountable on a fishing rod;
FIG. 2 is a top plan view thereof;
FIG. 3 is a right side elevation view thereof;
FIG. 4 is a left side elevation view thereof;
FIG. 5 is a rear elevation view thereof;
FIG. 6 is a bottom plan view thereof;
FIG. 7 is a front perspective view; and,
FIG. 8 is a front perspective view, shown in use.
The broken lines shown in the drawings are for the purpose of illustrating environmental matter and portions of the article that form no part of the claimed design.