# Light sensitivity



## PaulLamb (Nov 15, 2009)

One of my gambusia males started having an extreme reaction every time I turn on the aquarium lights in the morning (or after turning them off for a couple of minutes then back on). He jerks violently, becoming paralyzed, and begins floating in the current upside-down/sideways/backwards like a dead fish. He occasionally jerks his tail for a half-second, shooting off in a random direction. These spasms increase in frequency until he eventually regains control after one of these episodes (takes about a minute, but varies). Afterwards he seems perfectly normal, swimming around and bickering over food.

I am wondering if anyone has seen this kind of behavior before and can identify the cause. If it is a disease, I will need to cull him and treat the remaining fish. If it is a genetic disorder, I need to cull him, his parents, and all siblings and offspring to ensure this problem doesn't pop back up again later. If its a reaction to something in the water, I need to know how to treat that as well. Any ideas?


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## Peeps (May 24, 2010)

He might be scared with the lights turned on all of a sudden. Try turning your home lights on first in the morning. Then turn the tank lights on if it's dark. But that's all I can think of. I used to have a shark that did the same thing and when I turned on the hiome lights on first he adjusted better.


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## PaulLamb (Nov 15, 2009)

I'm not really interested in making accommodations for him (I can easily walk down to the nearest lake and net as many replacements as I need). My main concern is knowing if this is a random genetic disorder or if it is a symptom of a more sinister disease that could spread to the other fish in the aquarium.


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## Corwin (May 23, 2010)

just so that you dont come across as heartless, the gambusa's were the ones you intended to breed into demesticity correct? So you would be looking at this more from a point of avoiding a possible issue latter on (an entirely domestic fish that needs total darkness) correct?


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## PaulLamb (Nov 15, 2009)

Corwin said:


> just so that you dont come across as heartless, the gambusa's were the ones you intended to breed into demesticity correct? So you would be looking at this more from a point of avoiding a possible issue latter on (an entirely domestic fish that needs total darkness) correct?


Right, the concept of culling to eliminate genetic defects and improve a breeding line is not new.


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## TheOldSalt (Jan 28, 2005)

This is a common symptom of toxicity, usually nitrite. Heavy metals can do it, too.
I would eliminate that fish from the program just because it is apparently overly sensitive compared to the others; not a good trait to pass on to later generations.


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## dan3345 (Jan 27, 2010)

As stated above this could be nitrate burns or simply the fish being afraid of the sudden change in lighting. Do you have a testing kit? And also if you test the water and it turns out fine, then do what Peeps suggested, I don't know why making a very small accommodation for a fish is so hard, and why you would resort to culling the fish.. If it's because you are breeding a specific gene, then culling that fish isn't going to cause future generations form another fish from doing the same thing. Its just a reaction, and it shows the fish is afraid.


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## Corwin (May 23, 2010)

his reason for doing it was if it was a genetic disorder he didnt want to run the risk of it re-occuring. It seems however that its not a genetic thing, in which case i would assume that he wouldnt cull them.


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## PaulLamb (Nov 15, 2009)

I tested the water, and the levels are fine (although I don't have a way to test for heavy metals). If this is not a disease, then the problem is most likely either genetic or possibly brain-injury or tumor-related.



dan3345 said:


> if you test the water and it turns out fine, then do what Peeps suggested, I don't know why making a very small accommodation for a fish is so hard, and why you would resort to culling the fish.. If it's because you are breeding a specific gene, then culling that fish isn't going to cause future generations form another fish from doing the same thing. Its just a reaction, and it shows the fish is afraid.


It's not an issue of a small accommodation - its an issue of this behavior, whether it is a neurological disorder or an over-sensitivity, being passed down to future generations. While your concept of humaneness sounds heroic in writing, it is impossible to selective-breed without using culling as a tool. 90% of the aquarium fish would never have existed without it. It is simply impossible to accommodate every single fish, all their offspring, all their offspring (and so-on exponentially). I could go the route of "finding homes" for the undesirables, but I guarantee you that 99% of anyone buying gambusias is using them for mosquito-control, and many of them could wind up being introduced into new environments to wreak havoc on native fish populations. Decisions have to be made which fish you are going to keep, and which ones have to go. It isn't even a hard decision in this instance. I've just started out on this selective-breeding project, and I must ensure that my foundation stock are the hardiest, most genetically sound fish that I can find.


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## dan3345 (Jan 27, 2010)

PaulLamb said:


> I tested the water, and the levels are fine (although I don't have a way to test for heavy metals). If this is not a disease, then the problem is most likely either genetic or possibly brain-injury or tumor-related.
> 
> 
> 
> It's not an issue of a small accommodation - its an issue of this behavior, whether it is a neurological disorder or an over-sensitivity, being passed down to future generations. While your concept of humaneness sounds heroic in writing, it is impossible to selective-breed without using culling as a tool. 90% of the aquarium fish would never have existed without it. It is simply impossible to accommodate every single fish, all their offspring, all their offspring (and so-on exponentially). I could go the route of "finding homes" for the undesirables, but I guarantee you that 99% of anyone buying gambusias is using them for mosquito-control, and many of them could wind up being introduced into new environments to wreak havoc on native fish populations. Decisions have to be made which fish you are going to keep, and which ones have to go. It isn't even a hard decision in this instance. I've just started out on this selective-breeding project, and I must ensure that my foundation stock are the hardiest, most genetically sound fish that I can find.


I was not saying to do anything too humane. All I was saying was that if a snigle fish has a over fear of light, then culling that fish is not going to stop the future offspring of another fish from being afraid. If the fish is afraid its going to be a afraid. And eliminating a single fish is not going to stop others from showing similar symptoms from fear. 

And may I ask what you are breeding these fish for?


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## Corwin (May 23, 2010)

He's attempting to create a domesticated gentler version


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## dan3345 (Jan 27, 2010)

Corwin said:


> He's attempting to create a domesticated gentler version


I get it, and maybe I just don't fully understand but it seems to me if a fish is afraid of something his offspring are going to be afraid or not. It's like if a woman has a fear of heights. Is her child going to be born with a fear of heights? i don't think so.


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## PaulLamb (Nov 15, 2009)

dan3345 said:


> I get it, and maybe I just don't fully understand but it seems to me if a fish is afraid of something his offspring are going to be afraid or not. It's like if a woman has a fear of heights. Is her child going to be born with a fear of heights? i don't think so.


Come on. You know as well as I that a normal fish, when it is afraid, does not go into a seizure-like episode. There is clearly something wrong with this fish, and it could very likely be genetic.


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## emc7 (Jul 23, 2005)

actually, anxiety disorders have a genetic component. So I would say her child has a higher than average chance of being afraid of something. 

It does sound like something akin to a seizure. Maybe you should breed a line of these for use in medical research or just as a novelty. Can't you just see the internet ad for "fish that play dead". I would cull it, but how much do "fainting goats" get?

I can't see it being a useful "escape from predators" method. When i startle a sleeping angel, it will often hit the lid. Its like, its programmed to jump out of the water to avoid a pike cichlid coming from below. So I try not to startle the angels.


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## dan3345 (Jan 27, 2010)

emc7 said:


> actually, anxiety disorders have a genetic component. So I would say her child has a higher than average chance of being afraid of something.
> 
> It does sound like something akin to a seizure. Maybe you should breed a line of these for use in medical research or just as a novelty. Can't you just see the internet ad for "fish that play dead". I would cull it, but how much do "fainting goats" get?
> 
> I can't see it being a useful "escape from predators" method. When i startle a sleeping angel, it will often hit the lid. Its like, its programmed to jump out of the water to avoid a pike cichlid coming from below. So I try not to startle the angels.


Im sorry I did not realize the problem was so extreme as to be compared to a seizure. my fish freak when I turn on the lights by darting in all directions, and then they calm down. But this only happens when it's dark and suddenly the bright lights come on.


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## PaulLamb (Nov 15, 2009)

emc7 said:


> Can't you just see the internet ad for "fish that play dead". I would cull it, but how much do "fainting goats" get?


I've always wondered what someone was thinking when they noticed the first "fainting goat" and decided to breed a variety with that trait (I'm guessing lots of dollar signs). Personally, I'm not that desperate for money..


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## mousey (Jan 18, 2005)

if it is any help- Somewhere along the line of home bred platies I have picked up a problem in the males that starts when they are about 7-9 months old. Util that point they seem very healthy. However they start to clamp fins and twitch and jerk.
I have tried treating for parasites but it has no effect. they continue to eat normally and do not lose weight. I suspect it is some kind of seizure activity but don't know for sure. It does not affect or spread to the other fish(Glo light tetras, guppies, loaches or cories).
Females seem not to be affected.
I wonder about the tetrahymena parasite in the tank if it is a cause but if so it likely would affect the other fish in the same way not just males. 
dunno if that helps- probably not.


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## Corwin (May 23, 2010)

somehow i doubt that breeding a line of fish that have siezures when exposed to light wouldnt be viewed as a cool novelty... infact i get the feeling it would be viewed as cruel lol.

As for the whole breeding project im really interested to see how well this is going to work. I hope all the best, and who knows maybee ill one day have a PaulLamb bread mosquito fish of my own


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