<p>Aquaculture is a rapidly growing sector that plays a crucial role in meeting global food demands and providing livelihoods. However, industry faces significant challenges from pathogens like <i>Aeromonas hydrophila</i>, which can lead to severe economic losses. Traditional treatments, such as antibiotics, have become less effective due to the rise of antibiotic resistance, necessitating the exploration of alternative strategies. This review explores the potential of photodynamic therapy (PDT) as an innovative approach to controlling <i>A. hydrophila</i> in aquaculture and evaluates its implications for sustainable practices. We conducted a comprehensive review of the literature on PDT, focusing on its mechanisms, the role of photosensitizers, nanotechnology, pathogen control, photocatalysis, and the generation of reactive oxygen species (ROS). We also examined the logistical challenges of implementing PDT in aquaculture and the need for optimized treatment protocols. Our findings indicate that PDT presents a promising alternative for pathogen control in aquaculture. It also highlights the potential applications of natural and synthetic photosensitizers, emphasizing their role in sustainable aquaculture practices. We also discussed the current challenges in implementation of PDT in aquaculture, logistical issues, light sources, and treatment timing. Integrating methodologies such as PSs and nanotechnology could enhance the efficacy of PDT in combating <i>A. hydrophila</i> and other pathogens. By addressing current challenges and optimizing protocols, PDT has the potential to contribute significantly to sustainable aquaculture, improving food security, and reducing reliance on antibiotics.</p>