The Sleeping Bag of the Parrotfish The fish shown in the picture
on the other page is called the parrotfish, since it resembles a
parrot, as you may have noticed. This colorful fish employs
quite an unusual method to protect itself against its enemies.
Especially at night, it covers its entire body with a gelatin-
like substance that it produces itself. Before answering the
question "why?", let's see how this substance is produced and
used. This gelatinous sheath of the parrotfish is secreted from
the upper side of the gill cavity. The fish secretes the
substance while it breathes. After a while this sheath covers
the entire body of the fish. By doing so the fish places itself
within a kind of sleeping bag and becomes protected from
external danger at night. This substance also enables the fish
to conceal itself by camouflage. As a vital function, the
transparent sleeping bag protects the fish from moray eels, one
of its bitter enemies. Moray eels have an excellent sense of
smell and can find their prey with i