The ornamental design for a flying clownfish balloontoy, as shown and described.
FIG. 1 is a left front perspective view of a flying clownfish balloon toy, the right side being a mirror image thereof;
FIG. 2 is a right side elevational view, the left side being a mirror image thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a top plan view thereof; and,
FIG. 6 is a bottom plan view thereof.
The broken lines showing the remote control and structural elements are included for the purpose of illustrating environment and form no part of the claimed design.