Objective. To assess the survival and growth of juvenile Pacific goliath grouper (Epinephelus quinquefasciatus) in captivity at low salinities. Materials and methods. We randomly selected twelve juvenile goliath groupers with an average standard length of 44.2 ± 6.1 cm and 1492 ± 476 g in body weight, and raised them for three months in the laboratory in waters of 32-26, 20, 10 and 5 parts per thousand of salinity. Results. All juvenile Pacific goliath groupers tolerated the initial gradual transfer from full strength seawater to salinities of 32-26, 20, 10, and 5 parts per thousand, which was done over a period of four days. All of them survived and grew in body weight and length during the course of the three-month experiment, in all the treatments of high and low salinity water. The body condition factor (K) for each fish was between 1.5 and 2.4. Conclusions. This is a first time trial that documents a randomized, controlled experiment demonstrating the ability of Pacific juvenile goliath grouper to gradually transfer from full strength seawater to water of lower salinity, and survive and grow well in these brackish waters.Key words: Aquaculture, euryhaline species, osmoregulation, water salinity (Source: BNA, NAL).