The Peacock gouper (Cephalopholis argus) was introduced to Hawai‘i in 1956 to establish a new fishery. It has become abundant, but the fishery failed due to concerns about ciguatera fish poisoning, a neurological disease in humans caused by ingestion of fish containing ciguatoxin. The aim of this study was to provide better understanding of geographic patterns of ciguatoxicity in C. argus and of the correlation of toxicity with morphometric characters of this species, with the goal to assess the possibility of a safe fishery. Overall, 18.2% of C. argus specimens from sites around O‘ahu and Hawai‘i Island contained ciguatoxin in concentrations potentially harmful to humans. This was higher than the rate of occurrence in Hawaiian reef fishes in general, and on the scale of ciguatoxicity in species banned from sale in fish markets. Toxicity was high around both analyzed islands. However, toxic individuals were significantly less common around O‘ahu than around Hawai‘i Island (8% versus 24%). Regular geographic patterns in toxicity within islands (e.g., gradients along coastlines) were not present, and variability in toxicity within each sample site was high. Toxicity was significantly but weakly positively correlated with C. argus length but not with fish condition (measured by length at weight). In conclusion, high prevalence of toxic individuals, variability in toxicity on all analyzed spatial scales, and low explanatory power of morphometric characters make the avoidance of ciguatoxic C. argus individuals difficult. A safe fishery for this species in Hawai‘i therefore does not appear feasible at present.