New fish were discovered that have the ability to glow in the dark! Biofluorescence (the ability to glow in the dark) is common in some species such as corals and jellyfish. This trait is not commonly associated with fish. After a series of diving expeditions, however, scientists discovered over 180 species of glowing fish. These fish were very diverse including cartilaginous sharks and rays and bony fish such as eels and flatfish.
The divers used blue lights, which simulate the ocean’s water, to see the glow from these animals. This works because the blue lights are a high energy color which the fish absorb. Meanwhile they emit neon reds, greens and oranges to create a beautiful light display. These are the colors in the light spectrum that are missing from the blue light that is present in the ocean.
Now you may be wondering: Why do these fish glow in the first place? There are several theories as to why this occurs.
The first possibility is that the light coming from the skin of a fish is helpful in communication with other fish. Many fish have colorful glowing stripes that serve as messages to other creatures. Similar to birds, these bright colors could be used to attract mates. Also, scientists have shown that only a fish with a yellow filter in its eyes would be capable of seeing the bright glowing colors, so the message or location of a glowing fish would only be seen by certain species.
Another possibility is that the fish’s glowing skin is helpful for camouflage. Now, this may seem counterintuitive at first. Why would you want to glow in the dark if you are trying to hide from predators? It is well known that many coral, however, do glow in the dark. So for fish whose habitats are primarily the coral reefs, glowing really does help them fit in to their bright surroundings.
Finally, the glow that some fish emit is used in order to capture prey. Some jellyfish lure their prey with their red glowing appendages and the angler fish, made so famous in Finding Nemo, uses a glowing growth attached to its head to attract smaller fish to eat. This is very similar to the way that insects are attracted to lights at night and then end up getting zapped.
So why is this fish glow so important? Well, jellyfish produce a glowing protein that has been used in scientific research relating to medicine. The glowing substance can be used to track particular types of cells or molecules whether it is cancer cells or contaminants in water. The ability to track particular things can give scientist insight into how diseases spread, how reproduction cells function and how cells are made. Essentially these glowing proteins have served scientists as “tags” for microbiology much in the same way that scientisst will tag certain organisms to study their movements in the wild and check-up on them routinely. As such, the glowing characteristic of these fish species could also prove important for the future of science.