Corydoras panda the entire fin area. The caudal peduncle is marked with a black band, this black band encircling the caudal peduncle from dorsal to ventral surface. The adipose fin, supported by a small fin spine, sometimes contains black pigmentation. The head is the same ground colour as the body, with a black mask surrounding the eyes, descending vertically from the fontanel, over each eye, and ending in a triangular wedge immediately before the ventral surface of the head. The pectoral fins are positioned immediately behind the operculum, and are usually oriented horizontally when the fish is at rest, extended in a
Operculum (gastropod) the shell of "Charonia tritonis" is a seal made by the Minoan civilization. Opercula of certain gastropods, especially varieties from the Red Sea, have long served as an incense material in ancient Jewish tradition, as well as Arabian cultures. The operculum of conch species "Strombus tricornis" and "Lambis truncata sebae" are most commonly used in regions near the Middle East. Opercula from these conches may be the onycha incense material which is described in the Book of Exodus. Operculum powder is also an important ingredient in Chinese and Japanese incense making. Here it is called ""bèi xiāng"" (Chinese: 貝香; "lit."