Kelly Young, age 8, of Redwood City, California, for his question:

Do fishes ever close their eyes?

Come to think of it, you never see a fish with his eyes shut tight. But this does not mean that he does not close them. In one way, you might say that a fish never opens his eyes. This sounds strange. But what do we do when we close our eyes? We shut down our eyelids of course. And our eyelids are made of thick skin that shuts out the light and hides our bright eyes. A fish also has eyelids—but they are not made of thick skin.

A fish’s eyelids are made of glassy clear skin that does not shut out the light. We can see his eyes and he can see out through his glassy windows. Actually he needs these special covers to protect his eyes from the water and from scratchy things that go floating by. To protect his eyes, he needs his special lids day and night. So they are sealed shut—