The first application of single molecule real-time (SMRT) sequencing to study the Pavona decussata transcriptome and provided more transcriptional information on coral bleaching. The phenotypic variations exhibited by P. decussata under natural heat stress highlight the differences in individual tolerance. Enhanced amino acid metabolism by the coral host and provision of organic carbon by the symbiotic algae could alleviate energy deficiencies in P. decussata under heat stress. The sustained downregulation of innate immune-related genes that were detrimental to the symbiotic relationship was a crucial factor in maintaining coral symbiosis.