Wording of this Handout:
How far down into the sea can light reach? About 375 feet (114 m). At that depth the temperature is close to freezing, and you would think that there would not be many fish around ... but scientists have discovered more than 2000 species of fish down there, as well as thousands of other creatures.
And what's even more amazing is the fact that hundreds of these fish carry their own light with them.
But the fish don't make this light themselves. Instead, they have special pouches, near their fins or tails, and in these pouches they carry special kinds of bacteria (germs).
What makes these germs special is the light they produce.
The fish are equipped with shutters, which work like our eyelids. When the fish decide to, they can open or close their shutters, to either turn their light on or off.
The fish need the bacteria, (probably to attract food, or to dectect each other in the darkness.) and the bacteria would die if it were not for the fish.