Females have a short, rounded body shape, while males are slimmer and longer. The pectoral fins of females are short and rounded at the end, while males have longer pectoral fins, pointed caudal ends, and chasing stars on the pectoral fins during the breeding season. The female's abdomen is soft, from the abdomen to the anus, hard prongs are not obvious, and the abdomen is inflated and rounded during the breeding period; the male's abdomen is harder, from the abdomen to the anus there are obvious hard prongs, and it is not inflated during the breeding period.