I don’t know of many predators with UV vision that UV camouflage would help protect against. One of the few is the Mantis Shrimp. Much has been said about the “amazing” vision of the Mantis Shrimp. The capabilities of mantis shrimp ARE amazing, but you should be aware that no one species has all the capabilities spoken about as part of Mantis Shrimp vision – it’s a case of a lot of them each having one or more facets. But it has indeed been suggested that their UV vision is used, in part, to locate prey ( https://en.wikipedia.org/wiki/Mantis_shrimp , especially note 24) That being the case, it wouldn’t surprise me if their potential prey tried to blend in in the ultraviolet as well as in the visible (clean water provides excellent UV transmission, by the way.)
Most UV vision I know of, though, is by things like bees, who use it to locate pollen and nectar – flowers do the opposite of UV camouflage, making themselves VERY visible in the UV, standing out like neon signs against the humdrum non-UV would of chlorophyll.