The Science Behind Why Fish Glow

[SantaMonicaHelp]

Hello, my name is Cavan Smith, and I'm an intern for Santa Monica Filtration. Light has a huge influence on fish tanks, which gets me to think about light and fish simultaneously. I mainly research organic chemistry among other scientific fields, yet I still retain a strong curiosity in sub-classes of biology.

The process of bioluminescence hasn't been determined in every animal that- well... glows, but scientists have figured out numerous mechanisms that may be unique depending on the animal. In this post, I am going to be predominately talking about fish.

On an atomic basis, the general term for a light-emitting organic compounds is Luciferin. Think of Luciferin as more of a class of compounds; containing multiple different compounds that correlate with different types of fish. So now that we know that Luciferin is responsible for organic light-emission, how does it work? In the simplest terms, the compounds are oxidized (meaning they gain an electron) and react with the fish's corresponding enzymes to form a modified compound of a fish's Luciferin and energy in the form of light! Other ways include a bacteria containing a Luciferins being transferred from birth.

It has historically been hard for scientists to run test on Luciferins because they are typically reacted rapidly and on a small-scale. However, scientists have been able to isolate and recreate some of these compounds from certain fish. For example, scientists have isolated the luciferin named Vargulin from the Sea-Firefly (AKA Vargula hilgendorfii.) The Sea-Firefly cannot activate it's unique abilities unless it consumes a species that contains that exact same luciferin, Vargulin. This isn't the same for all fishes, but scientists are left baffled why the Sea-Firefly can secrete the enzyme needed for the reaction, but not the compound responsible for their glow.

Scientists have been, and are currently synthesizing their own Luciferin-like compounds. Each organic compound is completely unique from the next, but some synthetic compounds that are basically a slightly altered luciferin compound have been shown to illuminate!

Feedback is greatly appreciated. I will be updating this thread as well.

- C. Smith

References:
https://en.wikipedia.org/wiki/Vargulin
http://www.sciencedirect.com/science/article/pii/0378111995006761
http://link.springer.com/article/10.1007/BF02101634
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC432574/
https://books.google.com/books?id=DNrTfH5PcWoC&pg=PA64

 

[melypr1985]

Interesting, but I admit, hard for me to follow all of it. My comment may not even be totally on topic but I figured I'd give it a go.
Most of the "glowing fish" wont be found in the trade correct? Aside from a select few like this one:

They state that the glowing mark under the eye is made by luminescent bacteria. Is this not this same deal as the Luciferins your speaking of? Do the Luciferins only apply to the deep water glowing fish like this:

I did look up the sea firefly which is a crustacean... I've never heard of them or known there were glowing crustaceans! Super cool!

 

[SantaMonicaHelp]

Interesting, but I admit, hard for me to follow all of it. My comment may not even be totally on topic but I figured I'd give it a go.
Most of the "glowing fish" wont be found in the trade correct? Aside from a select few like this one:

They state that the glowing mark under the eye is made by luminescent bacteria. Is this not this same deal as the Luciferins your speaking of? Do the Luciferins only apply to the deep water glowing fish like this:

I did look up the sea firefly which is a crustacean... I've never heard of them or known there were glowing crustaceans! Super cool!

On topic or not I appreciate the reply! That is correct, most of these fish/marine-life cannot be found in conventional trade, or people don't know the mechanics. A lot of marine-life that uses luciferins are deep-sea, making it even more difficult to unravel what's going on with the fish. If I was living miles down in the ocean, surrounded by high pressures and high temperatures; I would hope I would atleast get to glow On the bright side, luciferins can be bacterial and don't only apply to deep-sea fish. What fish bioluminescense fish do you own?

- C. Smith

 

[melypr1985]

What fish bioluminescense fish do you own?

- C. Smith

Not a single one myself. But we did have the "flash light fish" for a while at the store in one of our displays. They were pretty cool, though I dont know what happened to them since I didn't work there at the time.

 

[watchguy123]

There are some GMO freshwater fish, GLOFISH, that have been approved for import to the USA. Although I am not all that familiar with it, the history of GLOFISH is pretty cool and can be found by googling GLOFISH

I saw a tank of them in an LFS. It's pretty weird and amazing.

 

[SantaMonicaHelp]

There are some GMO freshwater fish, GLOFISH, that have been approved for import to the USA. Although I am not all that familiar with it, the history of GLOFISH is pretty cool and can be found by googling GLOFISH

I saw a tank of them in an LFS. It's pretty weird and amazing.

Huh... I've never heard the term "GloFish" until now. They do look pretty cool; any fish genetically modified by fluorescence proteins would .

- C. Smith

 

[Maritimer]

The "GloFish" work best under black-light UV fixtures . . .

I've also been intrigued by the biofluorescence that some fish exhibit - kind of like our corals. I've seen images of biofluorescent sharks and sea-turtles, but the only common reef fish I've seen in the market is the Solor fairy wrasse, Cirrhilabrus solorensis, which exhibits a deep red fluorescence under blue lighting.

Can't wait to get mine under the blue lights of my display!

~Bruce, who keeps no bioluminescent fish, but has seen flashlight fish at a public Aquarium many years ago.

 

[SantaMonicaHelp]

but the only common reef fish I've seen in the market is the Solor fairy wrasse, Cirrhilabrus solorensis, which exhibits a deep red fluorescence under blue lighting.

Is the Solar Fairy Wrasse naturally biofluorescencent, (unlike GloFish)? I don't know much about the species to be honest, but I read that they aren't found in extreme dephs; thus making me think that they are commonly genetically modified. I'm curious to know, because I know the genetic modification of some GloFish has led to issues.

- C. Smith

 

[Maritimer]

Naturally - there's a bit about the study here:

https://www.sciencedaily.com/releases/2014/05/140528104024.htm

Fairy wrasses aren't typically bred in captivity at all, so wouldn't be a good candidate for genetic mods.

~Bruce

 

[SantaMonicaHelp]

Interesting, very interesting indeed @Maritimer . The article states, and I quote: "first time that fish are able to perceive their own biofluorescence and to use if to communicate with members of their own species."
I'm definitely going to research the Solar Fairy Wrasses a lot more now. Thank you for linking me to the article! I sincerely appreciate it.

I believe that the Fair Wrasse uses Phosphorescence to emit it's spectacular light. Phosphorescence is a type of photoluminescence that directly relates to the emission of fluorescence lighting. Unlike Luciferins, you do not need a reaction to take place in order to get the species to glow. (Luciferins react with enzymes.)

Here are some cool facts, and hopefully they will hopefully articulate my writing better: Phosphorescence is used 'glow in the dark toys', like those stars kids would put all over their ceiling- something that I did during my childhood. Luciferins require a reaction in order to "light up". An excellent example are glow sticks! A glow stick will not glow until you create a chemical reaction, which is simply done by bending a glow stick until your hear a snap. [WARNING I AM NOT REFERRING TO BREAKING THE GLOW STICK OPEN.] When making (most) glow sticks emit light, you are actually doing an oxidation reaction (oxidation=electrons are lost) of the Firefly luciferin, found in fireflies. Glow sticks do not have an enzyme that receives luciferins like all luciferin containing animals, so this is the main reason glow sticks degrade overtime; their Luciferin do not have an enzyme to bond.
I hope you found this helpful, or at least interesting... sorry, I'm kind of a nerd

- C. Smith

 

[SantaMonicaHelp]

Kind of off topic from this thread, but I couldn't help notice that you are an 'Article Contributor' @melypr1985. First off, congratulations on that commendation, and also all your other commendations I have not mentioned. How did you receive the stature of being an 'Article Contributor'?
I'm asking purely out of curiosity.

- C. Smith

 

[melypr1985]

Kind of off topic from this thread, but I couldn't help notice that you are an 'Article Contributor' @melypr1985. First off, congratulations on that commendation, and also all your other commendations I have not mentioned. How did you receive the stature of being an 'Article Contributor'?
I'm asking purely out of curiosity.

- C. Smith

I was already writing articles for the ReefEdition before they switched formats for that, so I simply asked if I could continue to do so.

 

[Squid]

I don't have much to contribute other than I went to a bioluminescent bay in Puerto Rico a few weeks back lol. Even touched a little glowing jellyfish

 

[SantaMonicaHelp]

I was already writing articles for the ReefEdition before they switched formats for that, so I simply asked if I could continue to do so.

That's awesome! I see you around the forum a lot so I became curious. You seem to be quite popular haha. Thanks for contributing.

I don't have much to contribute other than I went to a bioluminescent bay in Puerto Rico a few weeks back lol. Even touched a little glowing jellyfish

That's a pretty big contribution in itself. An entire bay of bioluminating aquatic animals?! That sounds amazing! Especially since a lot if not most bioluminescence or luminescence fish are found in deep waters. Whenever I hear the word luminescence I think of Anglerfish; interesting class of fish. Some have bioluminescence, some have luminescence, and some have neither- but the light always illuminates (if they can "glow") from their esca.
The esca is the fleshy-growth attached to an anglerfishes head.

Really weird and mysterious class of fish.

- C. Smith

 

[fk3212]

GloFish is a type of freshwater fish that has been genetically modified to give them an amazing glowing color.

You can get these awesome-looking guys in many different colors like:

• Electric Green
• Starfire Red
• Cosmic Blue
• Sunburst Orange
• Moonrise Pink
• Galactic Purple

Glo-Fishes come with patented breeding technology, so they’re highly sought after by many fish keepers all over the world in the aquarium hobby!