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 (fish) over time. The fossil record of the threespine stickleback provide the ancestral shapes of the operculum bone. Overall, the operculum bone became more triangular in shape and thicker in size over time. Genes that are essential in the development of the opercular series is the Eda and Pitx1 genes.These genes are known to be a part of the development and loss of armor plates in gnathostomes. The Endothelin1 pathway is thought to be associated with the development of the operculum bone since it regulates dorsal-ventral patterning of the hyomandibular region. Mutations in Edn1-pathway in zebrafish are known to lead to