Ask around you mates, work and neighbors and see if you can borrow some coolers. You may also be able to hire a decent sized ones from a commercial catering hire place. You will then need to decide if you go the dry ice or ice route for keeping the fish cold on the way home.

Another possibility is borrow a small chest freezer that will fit in your car (how big is the car? How big would a freezer need to be?), and get a 12V-mains pure sine wave inverter to run it while driving and power it when stopped for the night from mains.

Ask around, like your mates at work and neighbors and see if you can borrow some coolers. You may also be able to rent a decent sized one from a commercial catering company. You will need to decide if you want dry ice or normal ice for keeping the fish cold on the way home.

Another possibility is to borrow a small freezer that will fit in your car (consider how big is the car, and how big can the freezer be?). Use a 12V-mains pure sine wave inverter to run it while driving and power it when parked for the night from an AC outlet.