Guppy breeding questions?

If you really want the fry to survive, don't leave them in the 14-gal tank- the adults will eat them! And you said that you went from 14 fry to 7... did you check to see if the filter sucked than up? That could be the reason your fry are disappearing. :( What I do, is when the females are ready to give birth- dark gravid, large, boxy stomach, I move them to a seperate, smaller tank (your 3-5 gal would be perfect!), and make sure there are plenty of hiding places and plants (real or fake, though I like using real plants) for the fry to hide in. Don't forget to make your filter fry-proof by putting panty hose around it, or removing it alltogether! After the female has given birth, wait a few hours as she will be tired and stressed before putting her back in the main tank. Feed the fry flake food crushed into powder, some brine shrimp, and cooked egg yolk. As for the number of females in your tank, the best ratio would be 2 or 3 females to every one male. You could, however, have a tank of just females (many of whom already pregnant, I'm assuming). In that case, I would have maybe 6, 9 guppies max in there, since you will get a lot of fry, which, when fully grown, will take up A LOT of space. Oh, and the females might be dying because of the stress.. you might have too many males in your tank that are harassing the females, or it might be because of the breeding trap, which is just another reason that I don't use them. Anyway, good luck! Hope you get a lot of cute baby guppies swimming around soon! :D