Pump Question?

I have a '91 V-20 Cuddy with a large fish box in the floor between the seats. It had a pump of some kind mounted between the fish box and fuel tank but was removed for some reason. I checked the wiring and found that a switch on the console would control the pump. What type of pump should be used here? I assume the inlet would hook to the fish box and the outlet to overboard. I only use this space for storage now, but may need it for fish someday. I would really like to find more info on this boat for reference.