Coral reefs are threatened by a range of factors, including climate change, ocean acidification and pollution. Many of these are linked to oil and its derivatives being released into marine environments. Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants that accumulate in marine organisms and biomagnify throughout the food web, intensifying their toxic effects at higher trophic levels; in the case of corals, they have carcinogenic, mutagenic and teratogenic effects, including bleaching. This study investigates the biodegradation of a high-molecular-weight PAH, benzo[k]fluoranthene (BkF), by four different bacterial strains isolated from corals of the genus Pocillopora in La Paz, Baja California Sur, (Pseudomonas sp., Staphylococcus sp., Bacillus sp.) and a consortium from the same strains (Pseudomonas sp. and Bacillus sp.) cultured in Zobell’s medium at 35°C with agitation at 110 rpm for 120 hours. Samples were collected every 6 hours. Bacterial growth and degradation were analyzed using optical density (OD), and BkF degradation was determined by high-performance liquid chromatography (HPLC-UV), together with stable isotope analysis of carbon (δ13C) and nitrogen (δ15N). The latter was conducted to understand the mechanisms of biodegradation. In most strains, contaminant degradation exceeded 60%, with morphological changes observed following exposure to BkF in both colonies and cellular composition; whereas in the consortium, both strains exhibited adaptive behaviour and potential co-metabolism. Future applications of bacterial consortia and the development of in situ strategies in affected coral reefs could improve survival rates in restoration of reef ecosystems.