Shes Dropped

[susankat]

so this is the same for all livebearers then?

well mainly guppies as they are crossed with endlers.

but not as common for platys to be hybridized with swordtails. but guppys are highly and intensly farmed

This is a false statement concerning guppies being crossed with endlers to cause this affect. What causes this can have many varibles one being stress, the female being young or bad stock. Even the male could have been young or bad stock to cause this.

Most guppies or endlers are not entirely hybridized with each other but with guppies it is for the most part being inbred for such a long time that it has caused a weaker gene. As it is with many fish that has been inbred for different traits.

I have seen many endler/guppy hybrids and they are very healthy and produce viable healthy young. In fact I have 1 pair of hybrids myself that have been having lots of live healthy fry. I also have many pure endlers in a large tank, that started out as 14 and is now up to over 300 in less than a year.

 

[LauraFrog]

The stuff about genetics earlier is only true with certain combinations of the parents... if you breed healthy fish together, you aren't going to end up with weak fry because there's nowhere for the weak genes to come from. Healthy plus healthy (GG + GG) does not allow for any weak fry at all, because there is no weak (g) gene present.

This just doesn't happen in nature - some of them are going to be sickly or weak anyway. The strength, growth rate etc. of the fry is controlled by far more than one gene, and it's the overall mix they inherit that matters. I would agree that it is likely the deformities/deaths are largely caused by inbreeding. This is why I still only have three guppies. I'm biding my time and searching long and hard for suitable breeding stock, even going so far as acquiring fry from breeders and growing them on to obtain decent virgin females.

 

[susankat]

You won't find to many deformed ones in nature either, because that is ones that is usually the first to get eaten by other fish. Called survival of the fittist. There also isn't that much chance in inbreeding in nature as there is more to choose from for mates.

When it comes to home aquaria and local breeders and such, there is less to choose from. Guppies are so inbred for their colors and tails, that the species is getting weaker. In most cases it would be best to cross with a wild stock from time to time to bring in new and stronger genes.

I can use an example of a pair of my angels that I had gotten in a growout contest. The parents of said fish were so inbred that most of the fry had bent dorsal fins so bad that there was a predominate hook on it. I got lucky and got 2 that didn't have that trait but I would not breed the 2 together as I would believe that most of the fry will be deformed in one way or another. There is also a chance that breeding them with different stock there will be a 50/50 chance that those fry would still have the same deformities.