Celestial Eye have deeper bodies and shorter fins, and have selectively bred for these features as required by the British standard. In recent decades, the Chinese have crossed Celestials with several other breeds, most commonly Lionheads, Ranchus and Pompoms, producing much larger fish with short ranchu-like fins and very deep, blocky bodies, often with nasal 'bouquets' (pompoms) and rudimentary headgrowths. Some of these crosses tend to be less animated swimmers, especially those that possess a short, sharply downturned, ranchu-like caudal peduncle with flared and short caudal fins, traits which are otherwise uncharacteristic for the breed. Such fish can be quite sedentary, spending
Operculum (gastropod) shell when the soft parts of the animal are retracted. The shape of the operculum varies greatly from one family of gastropods to another. It is fairly often circular, or more or less oval in shape. In species where the operculum fits snugly, its outline corresponds exactly to the shape of the aperture of the shell and it serves to seal the entrance of the shell. Many families have opercula that are reduced in size, and which are not capable of closing the shell aperture. Opercula have sometimes been modified: in the Strombidae the operculum is claw-shaped and is used