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what happens if a male and female from the same mother, siblings, try to mate? Can they? Are the offspring from the siblings infertile? Do the same problems that arise from human inbreeding affect fish?

Thanks,

Scheibe

In fish, it's called line-breeding and is often done to continue desireable traits. However, it's generally a good idea to introduce new blood into the line after a few generations. ...And that's as far as my knowledge on the subject goes.

My original guppies are siblings and I have quite a number of healthy offspring. I would assume the offspring are fertile, but I've separated out the males and females because it was NOT my intent to have fry in the first place. Heh.

~Meow. Thus spoke the cat.~

Like with any creature, line breeding not only perpetuates and hones in on the good traits of a line, but also the bad. Only one generation of line breeding is not going to show much effect really, but bringing in new blood with traits that will improve the weakness in your lines will keep your stock stronger.

My guppies could be considered line bred, I think. They breed with each other, mother, father, sister, brother, cousin, grandmother, grandfather...well you get the hint I'm sure...

I truly end up with beautiful fish...the only problem is after many many generations of this, they will lose some of their immunity without having new blood.

I recently added some new guppies at Leslie's asking, and lost a lot of my older blood, but do have some of the fry from my older generations...amazingly my teenagers and fry have survived, while a lot of the adults did not...

line breeding is great, just be sure you add some new blood once a year or so to keep up the immunities. Heidi

"I've got a great ambition to die of exhaustion rather than boredom." Thomas Carlyle