How do guppy tail fin genetics work exactly

biofish

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Hello fam. So I have a few fry that were born from their mothers who were pregnant from the store, so I hadn’t gotten a chance to breed them yet, and their tails are freaking me out a little bit. I thought depending on species or type of guppy, they usually had small even fins for normal guppies, large lush fins for premium guppies, forked fins for endlers, etc.

But my fry that were born have mostly normal even fins…. With one or two randomly long jut offs. Like. The fin just spikes out. And I know this isn’t a case of nipped fins because I have been watching them grow for months… these little random spikes.

Is this possible by breeding day, and endler guppy with a normal guppy? I had one endler guppy who accidentally got onto the female side of the tank awhile back and he now has a number of children that all have the forked endler tails.

But these ones? I’m just confused. Here’s pictures of three of them.
 

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Colin_T

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If either parent has a swordtail or odd shaped tail gene, then some or all of the young could carry and develop that trait.

Endler's livebearers are regularly crossed with the common guppy to improve the health and vitality of the offspring.

If you want to breed guppies, you need to separate the young females from the males and let the females grow up to maturity (at least 6 months old). Then find a nice unrelated male and put him with one or more of the girls. Leave them together for a week and he will impregnate her with a number of sperm packets, which she can use any time after that (for at least 6 months) to fertilise her eggs.
 
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biofish

biofish

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If either parent has a swordtail or odd shaped tail gene, then some or all of the young could carry and develop that trait.

Endler's livebearers are regularly crossed with the common guppy to improve the health and vitality of the offspring.

If you want to breed guppies, you need to separate the young females from the males and let the females grow up to maturity (at least 6 months old). Then find a nice unrelated male and put him with one or more of the girls. Leave them together for a week and he will impregnate her with a number of sperm packets, which she can use any time after that (for at least 6 months) to fertilise her eggs.
Yup! Since these ones were born I’ve since upgraded to completely separate tanks for my female and male guppies (and three separate tanks for the fry to grow in) and I separate them accordingly when I feel the fry are big enough.

When I was newer I had one tank with a divider between the genders but my endler male always found a way to cross. Only him too. No one else found his pathway. So now, flash forward a few months, he has A LOT of offspring. To the point where I can no longer tell which one my original endler is.

The fry in the pictures were born from whoever impregnated her at the store, because they were born while my lady was still in quarantine from the shop. And this is the only batch of fry so far with such abnormal tails.

My endler guppies mixes from the accidental cross over on the other hand all seem to either have the split tail or normal tails without any in between. So that’s why I was confused as to why this particular batch could get such whacky tails. I don’t recall seeing any swordtails in her tank at the store (and I don’t have any) but honestly guppy genetics are so messed up where it could very be possible that she had some swordtail genetics and passed them to her kids. Thinking about it now she actually did have genetic defect where her top fin grew out of her side rather than her back (didn’t notice till after I bought her) so I guess she already carried a messed up fin gene

Also that book looks very informative
 
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biofish

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WOW. THAT IS VERY DETAILED AND FASCINATING. I wish I paid more attention in biology understood it better (gotta brush up on punnet squares) but if I get the book it’ll probably make more sense. I didn’t realize so many different combinations were equally likely.
 

Colin_T

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The fry in the pictures were born from whoever impregnated her at the store, because they were born while my lady was still in quarantine from the shop. And this is the only batch of fry so far with such abnormal tails.
Female guppies can carry sperm packets for many months and she might have used a sperm packet that she got from a male back at the breeders 5 or 6 months before you got her.

There also might have been a spike tail male in her tank at the shop and he got bought before you got your fish. And it could have happened at the quarantine/ importer.
 

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