Help me find this manhua please

It is a Chinese BL manhua set in a historical imperial setting, where, during his childhood, the emperor once saved a dying fish. Years later, that very fish, driven by deep gratitude and affection, transforms into a human-like merman in order to stay by the emperor’s side and help him. In the meantime, the emperor suffers a serious injury—likely from war or conflict—which leaves him unable to walk. Due to certain circumstances, the merman is arranged to marry the emperor and becomes his constant companion, caring for him devotedly. Secretly, the merman searches for a way to heal the emperor and ultimately decides to sacrifice his own inner core—the source of his power. In a final act of love, he gives the core to the emperor, allowing him to regain his ability to walk. However, this sacrifice comes at a great cost: the merman loses his powers and his ability to transform again. Before the emperor fully understands what has been done for him, the merman leaves—possibly as a result of punishment or consequence for his actions. Only after his departure does the emperor realize the depth of the merman’s love and the sacrifice he made for him.