breeding mollies and guppies

Question
HiL I Recently Decided To Start Breeding Mollies And Guppies As Feeder Fish. I Bought 20 Feeder Guppies (some Already Pregnant) And Was Just Given Some Young Mollies (of Which I Dont Know The Sex Of). I Was Wondering If Could Keep Them All In The Same Tank And How To Set It Up. Also I Have A Problem With When I Put A Pregnant (about To Burst) In The Plastic BreederOnursery SystemL They Just Dont Want To Drop Their FryL And End Up Dieing 2-3 Days Later Even Though I Am Changing WaterL Cleaning Constantly And Still Feeding Them. Is There Another Way To Do This_ Please Help Me! I Want To Keep As Many Fry As Possible! Thank You.

Answer
Hi,
Yes, you can keep them in the same tank, as they are compatible, and both like hard, alkaline water.
However, in an uncycled tank there will be high levels of ammonia and nitrite present in the tank, which may kill the fry.
They need a tank of at least 30 UK Gallons (about 37 US Gallons) if you have 20 guppies and some Mollies as well.
Feed the pregnant females plenty protein foods such as bloodworms, brineshrimp and daphnia. Also give her a few peas every week or so.
When she gives birth in the main tank, use a fine net to gently catch the fry and put them in a separate 5 - 10 Gallon "nursery" tank. Keep the nursery tank simple, with sand (they might get stuck in gravel) and a few plants/ornaments to hide in. Feed the fry with baby brine shrimp and crushed flake food.
Never do 100 % water changes in the main tank or the nursery tank. Do 30 percent water changes every week, probably twice a week just now until they have given birth.

Good luck,
Kathryn