I Started on a Desert Island and Built a God-Tier Fishery

Retired soldier king Ye Chen takes over his family's deserted island to pay for treatment for his younger sister, Ye Wei, who has leukemia. A storm hits while he's at sea, and a mysterious blue light strikes him, activating the Ocean Heart System. Following the System's guidance, he catches an outrageously expensive spotted coral grouper, easing his sister's medical bills for the time being. After driving off provocations from a fishing tyrant on a neighboring island, he unexpectedly unlocks a hidden System quest, strengthening his resolve to protect the island...