fc3dedfd_Fireside_Girls___Disney_Wiki__Notes
[Episode] "Lawn Gnome Beach Party of Terror" [Patches] Aquatic Safety Patch [Notes] 
Earned by becoming lifeguards at Phineas and Ferb's beach party. Though not seen, the title of the patch could mean that they were practicing Aquatic Safety, or it could just be they went to the beach and none of them were injured and all swam safely. Earned by the whole troop.
Fireside Girls - Disney Wiki
Notes