Global warming threatens reef-building corals with large scale bleaching events. Before being too late, uncovering potential adaptive capabilities to increasing temperature becomes one of the major thinking of saving corals. This study presents two coral species (Platygyra verweyi and Isopora palifera) surviving from a reef with regular hot water influx via a nearby nuclear power plant exhibited completely different bleaching susceptibility to acute thermal stress, even though both species shared several so-called “winner” characteristics (e.g., containing Durusdinium trenchii, thick tissue etc.). For P. verweyi, no algal density declined in the corals within 3-days after directly transferring from 25 to 31°C. But, same treatment caused I. palifera losing >70% algal symbionts within 24h. Most distinct feature between two coral species was attributed to overwhelmingly higher constitutive superoxide dismutase (ca.10 folds) and catalase (ca. 3 folds) in P. verweyi than in I. palifera. Moreover, P. verweyi also contained significantly higher saturated and lower mono-unsaturated fatty acid, especially a long-chain saturated fatty acid (C22:0), than I. palifera, and constantly associated with symbiotic bacteria, Endozoicomonas, which was not found in I. palifera. However, antibiotics treatment and inoculation tests did not support Endozoicomonas directly contributed to the thermal-resisting capability. This study highlights that, besides association with thermal tolerable algal symbiont, high level of constitutive antioxidant enzymes in coral host would be crucial for coral survivorship in the more fluctuated and high temperature environments.