breeding fish - some questions

In the last couple of weeks I've bought a a mix of male and female
guppies and a pair of swordtails and kribs. The male and female
guppies were deliberately bought from different shops so as to ensure
that the male and females were not closely related.

However, I've just been reading on the web that tried to breed from
shop bought guppies is a waste of time, as must will be stunted and
bland, is this true, I've got no interest in breeding for commecial
purposes, it just seemed like something that would add a little
interest for both my daughter (who is mad about guppies) and myself.
Also does the same hold for swordtails and kribs?
Cheers


Brian