The ornamental design for a cap for fluidcontainer, as shown and described.
FIG. 1 is a front isometric view of a cap for fluid container showing the new design.
FIG. 2 is a back isometric view thereof, with the cap for fluid container depicted upside down.
FIG. 3 is a top plan view thereof.
FIG. 4 is a front elevational view thereof.
FIG. 5 is a bottom plan view thereof; and,
FIG. 6 is a back elevational view thereof, with the cap for fluid container depicted upside down.
The broken lines depict portions of the cap for fluid container that form no part of the claim. The dot dash dot broken lines depict the boundary of the claim that forms no part thereof.