Indeed. There is the fluorescent frog (this one https://www.nature.com/news/first-fluorescent-frog-found-1.21616 https://www.nature.com/news/first-fluorescent-f

Indeed. There is the fluorescent frog (this one https://www.nature.com/news/first-fluorescent-frog-found-1.21616 https://www.nature.com/news/first-fluorescent-frog-found-1.2...), but the fluorescent compound might well have evolved as protection against UV light. Some other animals have bile dyes in their tissues, and again they are only fluorescent by accident.