design: High-molecular-weight genomic DNA was extracted from muscle tissue of a wild-catched Phoxinus grumi individual. The DNA quality and integrity were assessed using agarose gel electrophoresis and a Qubit fluorometer. For library preparation, high - molecular - weight genomic DNA was fragmented into segments of approximately 20 kb. The SMRTbell library was constructed with the SMRTbell Express Template Prep Kit 3.0 (PacBio) following the standard protocol, which includes end repair, SMRTbell adapter ligation, and bead - based purification to eliminate unligated adapters and short fragments. The library was then sequenced on the PacBio Revio system using the Circular Consensus Sequencing (CCS) mode.