"Siphonophorae" is an order of marine animals from the phylum Hydrozoa that consist of a specialized medusoid and polyp zooid. Some siphonophores, including the genus Erenna that live in the aphotic zone between depths of 1600 m and 2300 m, exhibit yellow to red fluorescence in the photophores of their tentacle-like tentilla. This fluorescence occurs as a by-product of bioluminescence from these same photophores. The siphonophores exhibit the fluorescence in a flicking pattern that is used as a lure to attract prey.