UV vision is wide-spread across animals. Many coral reef fish species use the reflection of UV light to communicate with conspecifics, as most aquatic predators are UV-blind. This creates a secret communication system for prey fish to signal to others while minimizing their risk of predation. Exploitation of this system by a predator that can see UV light would likely help facilitate prey detection and increase predator efficiency. Recently, indirect evidence has emerged that the Indo-Pacific lionfish (Pterois volitans), a highly invasive predator in the Caribbean, might be able to see into the UV spectrum. We propose that UV vision might be an important, and so far overlooked, reason for lionfishs predatory success. Using an associative learning assay, we investigated lionfishs ability to discriminate UV from non-UV light and found the first behavioral evidence that lionfish can indeed see UV light. We also measured the UV body reflectance of lionfish and found that lionfish reflect UV light, suggesting that lionfish may communicate with conspecifics via UV vision. Further studies should investigate if the UV vision is more widespread in marine predators than originally thought, as well as continue to investigate the function of UV vision in lionfish and other predators.