How often are genetic defects?

I have a couple pet store guppies that were pregnant when I got them. I have them and their offspring in a separate tank. As they have matured I've separated out the males so I hopefully don't end up with a tank full of pregnant fish! One is having fry again tonight, I've seen 3 so far. From the last couple batches I've been seeing fish with what looks like scoliosis. There have been several out of each batch. My plan was just to let her use up stored sperm and then possibly mate her with one of my males but I don't want to add to the bad gene pool if she's going to keep dropping defective fry. I also don't have the heart to cull them because they seem to be happy and growing. I could possibly sell them as feeders since that's more of a "let nature take its course" thing.

Anyway ... what's my best plan of action?

 

Defects can occur naturally but they're more common place when fish are inbred. If the ones you got all came from the same source, then they could very well all have the same parents/relatives and be brothers/sisters/fathers/mothers/uncles/aunts etc... This will likely lead to a higher percentage of birth defects.

My advice would be if the fish aren't in any obvious pain and seem to be doing alright then just to let them be and let nature take its course. If some appear to be struggling or are in pain then some tough decisions might need to be made (euthanasia). I'm not sure anyone would want them as feeder guppies, no real reason why but I get the feeling that some people might be a little peculiar about feeding deformed guppies to their other fish.

I hope this helps!

 

Well I got my females from one store and my males from another in a different town. The males had come from someone that brought them to the store for credit. I've not bred them yet. The females were pregnant when I got them. Should I let them keep using up stored sperm or try to let them breed with my males? I've read that if they breed within about 24 hours after giving birth the new sperm will take over.

 

Guppies breed like there's no tomorrow. I started off with three and had 11 in no time at all and that's without making any real effort to save the fry. If I were you I would try breeding the females with your new males, it should help diversify the gene pool if nothing else.

 

Guppies breed like there's no tomorrow. I started off with three and had 11 in no time at all and that's without making any real effort to save the fry. If I were you I would try breeding the females with your new males, it should help diversify the gene pool if nothing else.

Yeah I know they breed like crazy, that's why I've kept them separate. I was hoping they'd run out of sperm soon but with all of the deformities I'm worried to let her keep having fry from the previous donor. Considering trading her for a different female ... and wondering what to do with the deformed fish ... I don't have unlimited space to keep them all and was really just hoping to keep babies until they grew enough to trade in at the LFS.