Corals come in a rainbow of colors, due to fluorescent proteins (FPs) these coral hosts produce. The high diversity and repeated evolution of these FPs indicates an important role in host biology, but we don’t know what that role is. By capturing fluorescent profiles using a custom low-cost fluorometer followed by experimental bleaching assays, we seek to understand the role of FPs in coral symbiosis maintenance and bleaching tolerance on Fijian coral reefs.