reaseing Minnows

Minnows??? Fathead minnows grow to 3" or more!!!

I believe you mean guppies or feeder fish like rosy reds. Get a bigger tank for your fish, first of all. Then put the guppies/feeders in the 10 gallon. Then get a net breeder, put the net breeder in the tank. Wait for them to breed, and BTW, you will need males and females . Then put the pregnant females in the net breeder, wait for them to give birth, then put the females back in the normal tank. The baby fish can be fed powdered flake foods. Get a ZIPLOC bag, put SOME flakes inside, crush, crush, and crush some more. Then, using a toothpick, put the toothpick in the bag and use it like a spoon. you should be able to get SOME powder on the toothpick. Then put the powdered food thats on the toothpick in the net breeder. Feed like this 2-3 times a day, making sure you DONT overfeed.

Repeat as needed.

I have no idea, since I have never used one. You can tell they're pregnant when the females are seem to look like they will explode. Fat bellys, hindered swimming, but don't mix pregnancy with illness.

5 gallons at the LEAST, 10 gallons would be the best for the fish and you'll get more fish this way.

You could set up a 5-10 gallon tank for the fish and put in plenty of plants, java moss, places the babies can hide once born and just add a bunch of roseys to start with and let them do their thing. I'm not sure how good they are as parents or whatever, you'd have to do some research. As long as the babies have a place to hide and grow there should be enough born to feed to your other fish.