Ranchu tail. The caudal peduncle itself should be broad and neither lengthy or too short (a properly formed caudal peduncle avoids swimming motion impairments to this type of goldfish). The ranchu's tail meets the caudal peduncle at a forty-five degree angle, giving the fish a unique swimming motion. Furthermore, the tail lobes are rounded, and all other finnage are paired. The most prominent feature of the ranchu is its head. There must be sufficient space between the eyes, and also from the eyes to the front of the head. The gill cover should figuratively extend quite far towards the tail. The
Operculum (gastropod) pentagram-shaped, and is used to dig into the sand to enable the conch to perform a leaping type of locomotion. The structure of the operculum can be described as follows: In 1998 Checa and Jimeneze proposed three types of opercula: There are two basic types of opercula in terms of their material composition: The different shapes of opercula can include ungulate (hooflike), claw-like, or ovate. The type and shape of the operculum is used to help identify and classify related groups (genera) of land operculates, and likewise some marine operculates. The oldest known human depiction of an operculum together with