{Reference Type}: Journal Article {Title}: New observations of fluorescent organisms in the Banda Sea and in the Red Sea. {Author}: Poding LH;Jägers P;Senen B;Limmon GV;Herlitze S;Huhn M; {Journal}: PLoS One {Volume}: 19 {Issue}: 6 {Year}: 2024 {Factor}: 3.752 {DOI}: 10.1371/journal.pone.0292476 {Abstract}: Fluorescence is a widespread phenomenon found in animals, bacteria, fungi, and plants. In marine environments fluorescence has been proposed to play a role in physiological and behavioral responses. Many fluorescent proteins and other molecules have been described in jellyfish, corals, and fish. Here we describe fluorescence in marine species, which we observed and photographed during night dives in the Banda Sea, Indonesia, and in the Red Sea, Egypt. Among various phyla we found fluorescence in sponges, molluscs, tunicates, and fish. Our study extends the knowledge on how many different organisms fluoresce in marine environments. We describe the occurrence of fluorescence in 27 species, in which fluorescence has not been described yet in peer-reviewed literature. It especially extends the knowledge beyond Scleractinia, the so far best described taxon regarding diversity in fluorescent proteins.