Bleak

Bleak (Alburnus lucidus), a small British fresh-water fish of the Carp family; found also in most European rivers north of the Alps. It is rarely more than 7 inches long, greenish or brownish above, and silvery white below. The upper jaw is protractile, but does not extend as far as the lower jaw. Bleak are cooked like sprats; and the crystalline deposit beneath the scales is used in the manufacture of artificial pearls, hollow glass beads being washed in the interior with this substance and then filled with white wax.