# RIP, Glofish.



## DarkCobra (Jun 22, 2004)

I'm not sure if anyone keeps these or if there's any interest. And I'm not looking for advice or an explanation, except perhaps for curiosity's sake.

I just wanted to share my experiences with them.

At one time I was quite fascinated with these. I had an unplanted 10G almost dedicated to them, with 50/50 actinics and a stark black and white scape to bring out their (un)natural beauty. Their hyperactive nature was also entertaining.

Things went fine until until females started to fill with eggs. One male went dominant, and relentlessly harassed the other males. Eventually the weakest ones started wasting away, then dying.

I hoped this was just an unusually aggressive male, so I removed him, then packed the tank with more to fill out the school size. A new male took up the role. More deaths.

Then I put that male and the largest female in a hastily assembled breeding tank, not really expecting anything. To my surprise, the next day there were eggs everywhere; and soon thereafter, tons of tiny little fluorescent red fish!

About 50 grew large enough to be transferred to various other planted high- and low-tech community tanks. No problems.

At least until my first 50% Python water change. Within a minute or two, every Glofish in that low-tech tank was floating dead. Every other fish was fine. What the heck?

That took out half my Glofish in one shot. 

Obviously, they're incredibly more sensitive to something than other fish, but I wasn't certain what. There's very little chlorine/chloramine in our water here, and I do condition; so I'm fairly sure it's not that.

Next test was with just a few Glofish. I carefully adjusted the fill water temperature to the tank temperature. Again, dead Glofish in about a minute.

More experiments followed. Even temperature adjusted, pH adjusted, conditioned, aerated, and aged replacement water still caused deaths. It took longer for death to happen, about 15-20 minutes; but they still went from apparently fine to dead or dying in about a minute.

Eventually I figured something out. 50% water change = dead Glofish. 33% water change = live Glofish with no ill effects whatsoever; even straight from the tap with no adjustments.

Weird.

So I moved the remaining Glofish to my 46G and resigned myself to 33% water changes on it.

It worked ok, but very rarely, one would suffer a rapid death, while the rest of the Glofish were unaffected. The ones I bred never showed any hint of aggressive nature, and got along fine.

So it went for years until yesterday, when I lost my last five Glofish. The only thing I did differently was to add a trickle of hot water from the tap, since the cold water was very cold. They were all approaching the end of their normal lifespan anyway.

I'm sorry to see them go, but also relieved; it's a load off my mind to do a water change without wondering if something is going to die.


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## mistergreen (Dec 9, 2006)

They shouldn't be any different than the ordinary zebra danio, except for the glowing gene.

You have to make sure if you have chlorine or chloramine. They're not the same in effect.


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## DarkCobra (Jun 22, 2004)

mistergreen said:


> They shouldn't be any different than the ordinary zebra danio, except for the glowing gene.


Yep. I've never kept regular zebra danios, so I can't tell you if they'd respond any differently. I did find a few scattered reports of people having the same problem with zebras; despite precautions against the usual suspects.



mistergreen said:


> You have to make sure if you have chlorine or chloramine. They're not the same in effect.


Water reports specify 0.5 to 1.5ppm at the tap, but don't say which is used. So I assume the worst and always use a conditioner effective against both.

I also use the recommended dose, which I assume is intended to neutralize a lot more than we have. We have great water here which I'm spoiled to, almost everywhere else I've traveled the tapwater tastes like bleach by comparison.

It's added before refilling with the Python and allowed to circulate a bit.

Even if it was this, I can't see it selectively killing one species so quickly, and leaving others completely untouched.

I would also think that if danios were so sensitive to chlorine that normal conditioning was insufficient, there would be a lot more danio owners pleading for help.

One additional monkey wrench in the chlorine possibility. I have never had a single Glofish die as a result of a water change in a non-planted tank, regardless of water change percent, or whether it was CO2 enriched or not.

Perhaps they're sensitive to TDS, which is raised by EI-style dosing, then suddenly lowered during the change. Or maybe sudden changes in dissolved oxygen. I may never know for sure.


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## Hoppy (Dec 24, 2005)

Very interesting! I was just researching these fish to see if I want to introduce them into a 45 gallon low tech tank I am starting on. I've had ordinary Zebra Danios before in low tech tanks, with no unusual problems, but that was years ago, before I ever heard of fertilizing. I think I will pass on these - too many other interesting fish available.


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## fishykid1 (Apr 5, 2010)

You realize that the Glo fish are injected with dyes and fed certain foods to make them that color.


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## HolyAngel (Oct 18, 2010)

actually.. they're not injected with dyes. GloFish have been genetically engineered with coral/other gene's to produce that color. There's a different type of fish, rasbora/tetra i believe, that has been injected/'tatooed' to look a certain color. GloFish are not that, but what I said, you can look it up ^^

anwways tho, outside of that, these were my first fish in my 29 gallon and while they didn't die immediately after a water change, they all died within 6months of buying them for no apparent reason while the cories, cardinals, and guppies all did fine. I had bought more at the 3 month mark due to 1-2 deaths I attributed to new tank syndrome because i couldn't find any other reason, but even then yeah, 3 months later they were all dead for no reason i can find.. I just never decided to buy anymore because of it. They definitely seem a bit on the sensitive/bad stock side. Could also blame Petco for that but I couldn't buy them elsewhere so i can't compare.


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## MrMoneybags (Apr 13, 2010)

you killed glofish/zebra danios?

is that even possible?


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## HolyAngel (Oct 18, 2010)

haha yeah thats what i heard before i got them, then lo and behold, reality slaps me in the face lol. Seriously tho, water params were good and have been and i still have all the fish i had then, i blame either bad stock, or that they're sensitive 

Just wanted to share my experience with them


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## wendyjo (Feb 20, 2009)

I've had problems with them as well, everything from wasting away, to dropsy, to curved spines. Proportionally I have had WAY more problems with them than with any other fish, including regular zebra danios. I've also bought them from different sources so that's not the issue.


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## DarkCobra (Jun 22, 2004)

wendyjo said:


> I've had problems with them as well, everything from wasting away, to dropsy, to curved spines. Proportionally I have had WAY more problems with them than with any other fish, including regular zebra danios. I've also bought them from different sources so that's not the issue.


I've seen the wasting away and curved spines as well. This reversed itself in a few when moved from the 50/50 actinic 10G tank, to my 46G planted. I wonder if they require a certain amount of normal light to be healthy, or particularly good water conditions?

Considering they're patented, and only those bred by the company are legal for sale, I also wonder if they have weak gene pools due to excessive inbreeding.

The ones I bred were far healthier than the store-bought ones, excluding the water change issue.


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## oaomcg (Sep 24, 2010)

fishykid1 said:


> You realize that the Glo fish are injected with dyes and fed certain foods to make them that color.


this is a lie


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## boringname (Nov 11, 2010)

There has to be a metabolic cost associated with the production of bioluminescence. Maybe this raises the oxygen needs of the fish and tap water was low in oxygen. I wonder if the tank had an air bubbler.


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## boringname (Nov 11, 2010)

http://en.wikipedia.org/wiki/Luciferase

"In luminescent reactions, light is produced by the oxidation of a luciferin (a pigment):

luciferin + O2 → oxyluciferin + light
The most common luminescent reactions release CO2 as a product."

---

I'm guessing glo fish need more oxygen.


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## oaomcg (Sep 24, 2010)

boringname said:


> http://en.wikipedia.org/wiki/Luciferase
> 
> "In luminescent reactions, light is produced by the oxidation of a luciferin (a pigment):
> 
> ...


are you sure this is the same luminescence seen in glofish?


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## lauraleellbp (Feb 3, 2008)

It sounds to me like maybe something is in your hot water heater? Or hot water pipes? Do you live in an older home/apartment?


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## DarkCobra (Jun 22, 2004)

boringname said:


> There has to be a metabolic cost associated with the production of bioluminescence. Maybe this raises the oxygen needs of the fish and tap water was low in oxygen. I wonder if the tank had an air bubbler.


They're not bioluminescent, they don't glow in the dark. (Although there are other genetically modified animals that do, very slightly.)

They're simply fluorescent. Like a highlighter or blacklight paint, near-UV that strikes them gets converted to another, visible color.

You are probably still right that there is a metabolic cost associated with production of a superfluous fluorescent protein.

There was a paper written about the possible environmental impact should Glofish be released into the wild, especially an existing zebra danio population. Apparently, if both plain zebra danios and Glofish are available, females of either type almost always choose plain male zebra danios to mate with. Evidence was presented that this choice is not based on appearance, but the quality of the males' mating dance; and it was concluded that Glofish males fared poorly because they just didn't have the same energy and endurance.

As for the oxygen level:

Straight from the tap, 50% water change causes almost certain death within 1-2 minutes, 33% water change almost always fine.
Replacement water vigorously aerated for 6 hours before 50% water change, no symptoms for about 15 minutes, then death occurs suddenly within 1-2 minutes.

So maybe oxygen has something to do with it, although I'd expect the aerated water to have plenty of oxygen in it by that time; or at least enough that it would perform better than 33% straight from the tap. Sadly I was running out of Glofish fast, and stuck with what seemed to work instead of continuing experiments.


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## DarkCobra (Jun 22, 2004)

lauraleellbp said:


> It sounds to me like maybe something is in your hot water heater? Or hot water pipes? Do you live in an older home/apartment?


About 30 years old. What contaminants would you suspect?


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## boringname (Nov 11, 2010)

http://en.wikipedia.org/wiki/Aequorin

"Aequorin is composed of two distinct units, the apoprotein apoaequorin, with an approximate molecular weight of 22 kDa, and the prosthetic group coelenterazine, a luciferin.

Mechanism of Action

The two components of aequorin reconstitute spontaneously, forming the functional protein.[citation needed] The protein bears three EF hand motifs that function as binding sites for Ca2+ ions. When Ca2+ occupies such sites, the protein undergoes a conformational change and converts through oxidation its prosthetic group, coelenterazine, into excited coelenteramide and CO2. As the excited coelenteramide relaxes to the ground state, blue light (wavelength = 469 nm) is emitted."

---

Yes, the glofish are florescent not biolumenescent. From googling around I think the fish glow from aequorin and the glowing both consumes 02 and produces CO2.

The glowing also seems to use up calcium. I think part of what fish are doing when they adapt to ph changes involves absorbtion and loss of calcium through the gill membranes. Maybe the glo fish have less calcium available to themselves or in the blood stream and this affects the adaptation to ph changes.


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## DarkCobra (Jun 22, 2004)

Aequorin is involved in bioluminescence. It chemically produces blue light.

GFP (green fluorescent protein), when it receives blue or near-UV light, re-emits green light.

In some jellyfish, both exist. They chemically produce blue light, which is seen as green because it's converted by GFP.

But in a green Glofish, only GFP exists. They glow fluorescently, only when exposed to the proper light. This requires no chemical energy, only light energy.

The only chemical energy demand is the original creation of the GFP, which is not consumed when it converts light fluorescently.


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## wendyjo (Feb 20, 2009)

The problems I had with them were never instant or after water changes - for me it was a slow process of watching them get worse over time. I do wonder if perhaps it was fish TB with the curved spines. But again, some of them wasted away and some developed dropsy. Oh and one developed some type of internal abdominal tumor. It was grossly disfigured and sort of bobbed around the tank rather than swimming smoothly. However, it lived a long time that way and didn't seem to be suffering as it had a normal appetite and all. 

Seems like basically these guys are just more likely to get almost any fish disease you can think of.


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## Hoppy (Dec 24, 2005)

wendyjo said:


> The problems I had with them were never instant or after water changes - for me it was a slow process of watching them get worse over time. I do wonder if perhaps it was fish TB with the curved spines. But again, some of them wasted away and some developed dropsy. Oh and one developed some type of internal abdominal tumor. It was grossly disfigured and sort of bobbed around the tank rather than swimming smoothly. However, it lived a long time that way and didn't seem to be suffering as it had a normal appetite and all.
> 
> Seems like basically these guys are just more likely to get almost any fish disease you can think of.


Inbreeding can cause that problem, and these fish are necessarily heavily inbred. The same is true when very selective breeding produces the oddly colored varieties of several fish. It is also a problem with dog breeds, especially when amateurs breed their dogs without regard for the potential problems. It is like human cousins mating repeatedly.


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## boringname (Nov 11, 2010)

DarkCobra said:


> Aequorin is involved in bioluminescence. It chemically produces blue light.
> 
> GFP (green fluorescent protein), when it receives blue or near-UV light, re-emits green light.
> 
> ...



I stand corrected.


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## norrmanndo (Jul 3, 2011)

I changed about 40% of the 46g water in my tank and 2 of 3 Glofish died. The other fish were fine. I think it could have been the oxygen because the Glofish were sticking their noses out of the water for a while. It seems 33% is the max change. Other fish = gourami, upside down catfish, 2 clown loach, algae eater, 4 neon tetra, 2 lantern eye tetra, and a few guppies. I put the chemicals to remove the chlorine before adding the water.


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## amcoffeegirl (May 26, 2009)

The glowfish i bought never made it through the night. i guess i didnt acclimate them though. ive had danios and they were very hardy. even the long fins


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## On The Rocks (Feb 13, 2012)

Bought a small tank for my daughter grabbed 20 neons, some guppies, a couple algae eaters two small angels and .... 10 of the pink glofish. Now i've lived in China for the last 10 years and bought all this here. 

The tank came planted and everything when you buy them so when I got it home I just filled with water and dumped in the fish. I know not the right way to do it but the fish here in China are very hardy. I didn't loose a single fish doing this.

By the way almost 40 fish and it only cost $6.35US! 

Now to my point. These glofish are crazy tough and they are aggressive. They are eating the tails off my neons and attacking each other biting each others tails off. Has anybody else seen these guys so aggressive?

I used to have zebra danios when I was younger and no problems at all but these guys are vicious! My wife wants to feed them to the chickens in our yard.

Is there a way to make them less aggressive or do they become chickenfood? My daughter likes them but she is also thinking to feed them to the cheickens as well.


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## Aquarist_Fist (Jul 22, 2008)

On The Rocks, what do you mean when you say "a small tank"? Zebra danios are not aggressive, but they do need a lot of room to swim. I know many people do it, but despite their small size, I would never keep them in anything less than 36". The original poster's aggression issue with the dominant male almost certainly would not have happened in a larger tank.


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## Jadenlea (Sep 15, 2011)

Mine all wasted away in a few months.. It has made me wonder if there is tb in my tank but maybe its just what glofish do


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