Morphometric and Histological Changes in Cyprinid Loach, Misgurnus anguillicaudatus, in the Early Growth Period

In this study, we measured the morphometric and histological changes in the cyprinid loach, Misgurnus anguillicaudatus, during the early period of growth. Eyes, yolk length, yolk height, and yolk volume of the larva decreased for 16 days post hatching (DPH) (P<0.05). During 60 DPH (P>0.05), the most anterior extension of the head × the posterior end of the supraoccipital, the most anterior extension of the head × the origin of the dorsal fin, the most anterior extension of the head × the origin of the pectoral fin, the posterior end of the supraoccipital × the origin of the pelvic fin, and the origin of the dorsal fin × the ventral origin of the caudal fin gradually decreased, whereas the most anterior extension of the head × the dorsal origin of the caudal fin, the origin of the dorsal fin × the origin of the anal fin, the origin of the dorsal fin × the origin of the pectoral fin, and the insertion of the dorsal fin × the origin of the pelvic fin gradually increased (P<0.05). In the cyprinid loach, the retina is composed of six layers: the epithelial layer, ganglion cell layer, inner nuclear layer, inner plexiform layer, outer limiting membrane, and rod and cone layer (RCL). After hatching, part of the RCL gradually increased in density. The kidney and midgut epithelium were already formed in the cyprinid loach just after hatching and grew gradually in subsequent days.