Fluorescent chromatophores with bluish white fluorescence were detected in the guppy Poecilia reticulata. These chromatophores were observable only by means of a fluorescence microscope, and could not be observed by a standard transmission light microscope or incident light microscope. Resembling other common chromatophores, these fluorescent chromatophores were dendrictic cells and similar to other chromatophores in the size, about 50–100 μm.

Of the 17 strains examined, these fluorescent chromatophores were detected only in the R strain, and in all 12 R strain individuals examined, each presented fluorescent chromatophores.

These differences in the occurence of fluorescent chromatophores among strains suggest that the formation of these chromatophores is the result of genetic polymorphism.