Pregnant Fish: What to do

I have two pregnant fish. A Sword and a black Molly. They both look like
they are going to explode. I was thinking when these fry come to just let em
fend for themselves but I recall someone here mentioning how the other fish
will eat them (I expect my pretty big clown loaches would gobble em up). I
do have one of those square fry net holders. Whats neccesary to feed them?
How many to expect from each fish? How long will they be pregnant before
producing?