Colonies of P. acuta were collected in Kāneʻohe Bay, Hawaiʻi in depths ranging from 1 to 4m, returned to HIMB, and placed in temperature and light controlled flow-through indoor tanks for acclimation. The ambient temperature was set to 26°C with light equivalent to local shallow reef conditions at 2m (Radion XR30w G3 Pro LED Light, EcoTech Marine). After one-month acclimation, eight coral colonies were cut into three parts for preconditioned (PC), non-preconditioned (NPC), and control treatments. Control and NCP corals were left at ambient temperature while PC corals were exposed toa preconditioning treatment (29°C for 72 hours; ramping at 3°C/hour) and then returned to ambient temperatures (26°C; decreasing at 0.125°C/hr). After two days, all corals were sub-fragmented, and fragments were allocated to treatment. Fourteen days after the preconditioning treatment, PC and NPC coral fragments were exposed to acute thermal stress when temperature ramped from 26°C to 32°C in ~2 hours. At 1h, 3h, 6h, 12h, 24h, and 72h after the initiation of heat stress, one fragment of each treatment (PC and NPC at 32°C and control at 26°C) was cut to ~1cm long pieces, washed with filtered sea water (FSW) and stored dry at -80°C.