# Guppy Fry Question.



## Magnum (Apr 6, 2013)

Not sure if this is the right place to ask this, but.... I have two female guppies (neon blue) and one male guppy (yellow leopard??) who have mated at least twice and have had two births with survivors. In the first birth, there were a total of four survivors. They have matured enough that I transferred them to my son's 30 gallon aquarium. They are all females. There are approximately a dozen survivors in the second birth (litter?) they were born about two weeks ago. Again, and I know it is still very early to determine this with any real accuracy, they all appear to be developing into females. There does not seem to be a single male in the two litters. This is the first time I have actively bred guppies so I do not know if this is common. My question is, do the rest of you who breed guppies have this experience? What is the normative female to male ratio in any given guppy fry litter? Is there any way to "tilt" the balance, so to speak, towards male guppy fry? Any information/clarification or advice would be truly appreciated. Thanks so much in advance!


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## Mykuhl (Apr 8, 2013)

I don't have experience breeding guppies but I do have experience breeding apistogramma and dwarf shrimp.
So I can say that in my experience usually not all fry will survive, even with the best care. You can have a significant amount tht do not survive, depending on different factors. I don't know how many were originally in each individual brood but because you have few survivors it is likely just a numbers game. For example in my latest brood of apistogramma....out of approximately 30 survivors it appears that I have mostly females. Although it takes a pretty long while to b sure with apistogramma. Some say that with these fish that the temperature of the water will affect the sex ratio. There are others that don't believe this to be true. I haven't looked into the validity of this myself to believe it one way or the other. Perhaps this is the same with guppies?


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## BillD (Jun 5, 2006)

At two weeks you will not be able to sex them.


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## Magnum (Apr 6, 2013)

Yeah, I have heard about the water temperature theory and that it is controversial. But your theory on it simply being numbers and survivors makes sense. I guess I will just have to wait and see what sex they turn out to be. Thanks for the reply.


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## Magnum (Apr 6, 2013)

BillD said:


> At two weeks you will not be able to sex them.


Bill, hi. The fry I transferred to my son's tank are about five weeks old, and to my untrained eye they certainly look female. At what point can one accurately determine the sex of guppy fry? The dozen or so in my 65 gallon are two weeks old, so perhaps some of them will turn out to be male. Thanks for your reply.


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## BillD (Jun 5, 2006)

You will be able to tell when the male's gonopodium develops. This will usually happen before any real colour changes. How long that takes will vary depending on temp and food. If I remember correctly, usually by around 6 weeks you should see the sex begin to show.


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## Magnum (Apr 6, 2013)

BillD said:


> You will be able to tell when the male's gonopodium develops. This will usually happen before any real colour changes. How long that takes will vary depending on temp and food. If I remember correctly, usually by around 6 weeks you should see the sex begin to show.


Ok. Thanks!


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## Fishfur (Mar 4, 2012)

If they are anything like Endlers, chances are there will be far more females than males in most broods. Nature prefers to err on the side of survival, and females have more value that way than males, since one male can fertilize a number of females. But you'll know when the sexual difference begin to appear.

As I recall, from the school days when I kept guppies, I always had far more females born than males. But modern guppy females are much more colourful than the ones that existed when I was keeping them. At that time, females had no colour at all.


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## Magnum (Apr 6, 2013)

Fishfur said:


> If they are anything like Endlers, chances are there will be far more females than males in most broods. Nature prefers to err on the side of survival, and females have more value that way than males, since one male can fertilize a number of females. But you'll know when the sexual difference begin to appear.
> 
> As I recall, from the school days when I kept guppies, I always had far more females born than males. But modern guppy females are much more colourful than the ones that existed when I was keeping them. At that time, females had no colour at all.


Yup. That makes a great deal of sense. More babies born to more females ensures a higher population. Lucky males, eh?  and you are right about the females being a lot more colourful these days. The two adult females I have that are having these broods are Neon Blue, their tails are quite beautiful. If anyone wants some young guppies let me know, I am going to soon have to thin out the herd!


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## tranceaddict (Apr 3, 2011)

you should be getting much more births. My guppies produce at least 20 spawn. per month. But they are mature.

I have noticed I'll get about a 1male to 2-3 females ratio.


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## Magnum (Apr 6, 2013)

tranceaddict said:


> you should be getting much more births. My guppies produce at least 20 spawn. per month. But they are mature.
> 
> I have noticed I'll get about a 1male to 2-3 females ratio.


That is quite a lot. Do you place them in a breeder box and thus separate your fry? If so, what do you do with them all once they get larger?


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## tranceaddict (Apr 3, 2011)

Once i see they gave birth in the main tank, Ill catch them and put them in a small tank till they are big enough to go back. the main gup tank is full of plants for the fry to hide it. Im sure some get missed too. 

Then I'll sell them to big al's for .50cents a pop once there adults. Helps with the supplies needed.


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## KeyLime (May 4, 2014)

It seems reasonable to infer that the high number of females is a result of environmental conditions. Fish even develop new organs in early life, like tadpoles do, which also depends on environmental conditions as to how and when organs develop. During this time gender is one of the issues resolved.



> Environmental factors influencing adult sex ratio in Trinidadian guppies.
> McKellar AE1, Turcotte MM, Hendry AP.
> Author information
> Abstract
> ...


Andrew Hendry is all science.


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