Jonathan Melnick, age 13, of Sarasota, Florida, for his question:

What are bathypelagic fish like?

Suppose you designed an assortment of impossible monsters. Let yourself go in the department of fearsome expressions and toothy jaws. Don't spare the clashing colors and bedeck your creations with a variety of neon signs and Christmas tree lights. Chances are, your artwork could pass for a group portrait of bathypelagic fishes. In real life, quite a collection of them can be fitted onto a page.

The word bathypelagic means creatures that belong to the deep ocean. This grim realm begins below the twilight zone and plunges three miles down to the ocean abyss. In the ocean trenches, it dips down six miles below the surface. No ray of sunlight ever penetrates this realm and the enormous pressure of water increases with depth. The temperature steadily drops to just a few degrees above freezing.

The surface swimmers cannot live here and no land animal could survive the crushing pressures. But bathypelagic dwellers have internal pressures equal to the water's pressure around them. Most of them explode when brought to the surface. They are specially adapted to the icy darkness and other hardships of their realm, but their biggest problem is food. Meals are few and far between and no plants live below the sunlit surface, which is miles above. The creatures down here devour each other and grab the crumbs of decaying plants and animals as they filter down from on high.

The six inch black swallower can gulp a 12 inch fish    down into his expandable stomach. Many others have rubbery stomachs of this sort    but their monstrous appetites are never satisfied. All of them have huge mouths and fantastically fierce teeth. Several have hinged fangs that act like trapdoors. Others have built in fishing lines. A certain deep sea gulper has a stringy six foot tail with a red light at the end. He dangles the light as a lure and lassoes his victim into his toothy jaws.

Many bathypelgic fishes have bioluminescent attachments that create cold light, somewhat like fireflies. However, their lights glow in vivid reds, greens and blues. As the hungry little hunters swim around, they add bright sparks to the midnight darkness    headlights, taillights and rows of shiny buttons.

It is a long way from the waves to the ocean abyss. Pressures and other conditions change on the way down and the various bathypelagic fishes are adapted to life at different levels. The number of species decreases with depth, though quite a sizeable collection of the little monsters are at home in the deep trenches.

Besides the fishes, many other creatures are at home in this grim realm. The crabs, lobsters and shrimp are larger than their relatives near the surface, and usually more colorful. There are deep sea sponges, jellyfishes and a large assortment of worms. Tough skinned sea cucumber have been found in even the deepest: trenches, 6 1/2 miles below the surface.