When to abandon a live bearer strain

[Garuf]

Hello hello

I’ve been keeping a turquoise flanked strain of endlers for about 2 years now, I had been selecting the nicest male, adding it to a tank of only females and then removing all the fry waiting till they showed colours and then splitting males from females.

Every few month I’d add new females, thinking I was improving genetics.

However I have been less ruthless lately and wanting to make life simpler moved to “natural” breeding with all the endlers in together and breeding without my selecting.

However this generation I have started to notice potbellied males, something until now I haven’t had and only seen in much weaker strains of things like guppies and mollies.

At what point do I abandon the strain, assuming that these deformities are now “in the genes” and not wanting to end up with weak lines like guppies?

I haven’t needed to cull before now, my breedjects have always had good body form so have been traded but is it now time to cull these males out?

I can rule out constipation, the body deformity started to show before colouring up.

 

[Carol]

Well from my point of view adding males would be better than girls. As a breeder of things I always felt it was better to develop a strong female line ,then pick outstanding males for stud and genetic diversity,to stop those recessive genes meeting each other.
Problem lies in that most fish are bred in similar places commercially so may well be more closely related than you would wish.
I used to amongst other things breed Corydorus Barbatus,they are renamed these days,we started with wild Sao Paulo fish. But of course unless you can get real outcrosses after about ten generations you get inbreeding depression. As I was breeding over several years in the thousands commercially we did develop a fault in the pectoral fins ,we lessened it but never totally got rid as pure outcrosses were just not available.
I think you might possibly be waiting too late for separation,as soon as you can distinguish a gonopodium get the boys out.
You might get that issue gone very quickly if you can get a real outcross. Depends if its a plain recessive gene . Unlike Dogs no one has sat down and listed what gene does what and how it expresses itself.
I personally would go for an outcross ,select the very best girls ,see what comes out first gen. If you do get a genuine outcross and it goes in the first gen,then its a pretty good bet its a plain recessive.
As we say in Dogs ,dont throw the baby out with the bathwater.

Do not be afraid to cull….ever…do not be afraid of inbreeding either ,as long as you cull…

 

[Carol]

Just a thought,I was speaking to the other half who belonged to quite a few Aquatic Society's round Bracknell ,Windsor area. He belonged to SLAG which probably no longer exists . Southern Livebearers something or other Group .
He suggested you see if you can find some groups in your neck of the woods where you could possibly find a member who has a long running strain that wont be related.
He also said he used a magnifying glass to spot those boys and get them out.

 

[pat1cp]

That is one unfortunate acronym.

 

[Carol]

Yes ,there were a lot of SLAGs in the Thames Valley all male Im told in the seventies and eighties. I hasten to add I lived on the South Coast by then .