Why would the fossil of an ocean fish found on two different continents not be good evidence for continental drift?

If the fossil of an ocean fish is found on two different continents, it could actually be very good evidence for continental drift. Continental drift is the theory that the Earth's continents have moved over time. If the fossil of an ocean fish is found on two different continents, it suggests that the two continents were once connected, and have since drifted apart.