I claim the ornamental design for a baseball hat shaped fish aquarium, as shown and described.
FIG. 1 is a perspective view of a baseball hat shaped fish aquarium, showing my new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a top plan view thereof, shown at a reduced scale;
FIG. 5 is a bottom plan view thereof, shown at a reduced scale; and,
FIG. 6 is a left-side elevational view thereof, the right-side elevational view being a mirror image thereof.
The broken lines showing stitching on the bill of the cap in the figures are literal etched lines formed in the design to represent stitching, and are part of the claimed design.
The broken lines in FIGS. 2 and 3 are for illustration only and form no part of the claimed design.