The name suits him so well, it seems like it must have been a fabrication. In fact the English telephone books abound with Bleaks, named not for the adjective but for the fish, Alburnus lucidus, a relative of the bream and the minnow.
“It is found in European streams, and is caught by anglers, being also a favourite in aquariums. The well-known and important industry of 'Essence Orientale' and artificial pearls, carried on in France and Germany with the crystalline silvery colouring matter of the bleak, was introduced from China about the middle of the 17th century.” (Encyclopedia Britannica, 11th ed.)
The fish is called ablette in French.