Reef halos are circular patterns of bare sand surrounding patch reefs, formed by herbivorous fish grazing near their reef refuges. These formations serve as indicators of ecological processes, providing insights into interactions among herbivores, vegetation, and predators. Their size and prevalence are influenced by predator and herbivore densities, fishing pressure, and temperature, making them valuable proxies for assessing the impact of anthropogenic stressors on reef ecosystems. Halos can also be monitored using satellite imagery and artificial intelligence tools, offering a scalable method for evaluating ecosystem health. In this study, we present the first spatially explicit agent-based model to explore reef halo formation.