The sailors in the submarine used a what to look at the fish?

Contrary to popular belief and myth, submarines (other than the one at Disneyland) do not have Windows or any other means of looking at fish or other creatures in the ocean. Submarines are sophisticated weapons, and fish aren't they're primary mission.

Submarine Sonar Techs (myself included) do hear fish when boats come to periscope depth and biologics (the technical term for sea life) surround the boat. While a periscope can catch occasional glimpses of fish, that's not its primary function.

The notion comes from the old '60's movie and TV show "Voyage to the Bottom of the Sea", featuring the fictional submarines Seaview. It had transparent hull plates on the very front of the boat. However in reality, submarines don't spend that much time at depths where fish are visible, and even then they don't tend to get close enough to see.