from what i have been told, as well as experienced killies generally like low lighting, during the day in bright lights my killies used to hide and generally do nothing, all my killie tanks are in a cupboard that i designed myself and is fairly dark, the fish love it, are always active...well basically always doing "it".
temperature is quite low really, around 22 degrees is generally the best, although everyone has their own opinions, mine fluctuates 21-24 depending on the day.
My killies live on flake food, sometimes they get a bit of microworm, although im not sure how much of it they eat, as with any fish live food is best.
breeding them is very easy, im having more luck with the killies than even my guppies, just requires a little bit of effort