About Opsariichthys pachycephalus Günther, 1868
Opsariichthys pachycephalus is a species of freshwater ray-finned fish that belongs to the family Xenocyprididae, a group known as East Asian minnows or sharpbellies. This fish species is endemic to Taiwan, and it is one of the most common minnow species found on the island. It occurs across the entire western portion of Taiwan, ranging from sea level up to 1,200 meters in elevation. It is a small fish, reaching a maximum total length of 16 centimeters (6.3 inches). Opsariichthys pachycephalus has two peak spawning periods each year: one in spring, from February to April, and a second in summer, from June to August. The spring spawning period is the main one for the species. During courtship, multiple males chase a single female, and the males exhibit aggressive behavior toward one another. Only the male that wins male-male contests will follow the female to spawn. After spawning has occurred, the male may return to the spawning site to chase away animals that prey on the species' eggs.
