Yes, jellyfish really do glow in the dark. However, most do not.
Many jellyfish have a completely transparent or translucent appearance. They are frequently displayed in public aquariums and hypnotically fade from one color to another. While watching these delicate creatures slowly fade from one color to another is certainly fascinating, it’s not the jellyfish itself that glows. This beautiful array of colors is simply a matter of colored light passing through the jellyfish’s membranes.
The species commonly known as comb jellies don’t need an elaborate lighting setup to produce their own disco display. However, they are not real jellyfish. They are also not bioluminescent. They just seem to be. Although closely related to each other, comb jellies are from a completely different phylum (Ctenophora) than jellyfish. Jellyfish use what can be more accurately described as jet propulsion as their means of locomotion. Comb jellies have 8 rows of combs, hence their name. These combs are the equivalent of thousands of tiny oars. They move through the water hitting these combs in sequence. Their combs are highly reflective and produce a mesmerizing disco-like light show as they move. Scientists speculate that this hypnotic light display acts to engage the natural curiosity of potential prey.
There is only one species of jellyfish that is bioluminescent,Aequorea spp. These jellyfish are more commonly known as Aequorea victoria or glass jellyfish. Its bilochemical light emission is produced by a combination of two molecules; aequorin and green fluorescent protein. Together they produce flashes of green light. GFP (Green Fluorescent Protein) has been isolated by a scientist and is being used in cell research. GFP was the protein that Dr. Zhiyuan Gong and colleagues at the National University of Singapore incorporated into the genome of zebra danio eggs to create the immensely popular freshwater aquarium fish, the Glofish. Further experimentation has progressed to the incorporation of this gene in mammals and, more recently, in primates. It should be noted that none of these genetically modified animals glow in the dark. However, they will fluoresce under a backlight.
Moon jellyfish do not glow in the dark. But they have translucent bodies. They look absolutely amazing with a variety of fading LEDs shining through them. Now you can buy a Jellyfish Fish Tank Aquarium to raise your own jellyfish as pets. You can even light them up as if they were in the aquarium’s large public jellyfish displays.
