Actually there are many strains of fruit flies because they have been used extensively in genetics research. A geneticist I encountered at a killie show, pointed out to me that we have a myth in the hobby that when the temperature of our wingless or vestigial fruit flies gets to a certain temperature, they develop regular wings. Actually, he suggested, warm weather means that there are a lot of live fruit flies cruising around and one of them (with the dominant genes) has snuck into the culture, despite the best effort to use a fiber plug to isolate the culture in the bottle.

I think we, who are aquarists, are learning from those who keep Amphibians and especially frogs. At our CKA meeting last Friday, one of the Chicago killie people brought in cultures of both the of small ones. They sold a lot more reasonably than through the catelogues.

You can slow down a culture of flies by putting them in a refrigerator. Freezing them will really put a halt to the parade, but I would shake the hatched ones out of a culture bottle into another bottle, so the culture can continue.

Fruit flies already pestering you in a kitchen can be caught and drowned if you leave out an open bottle of vinegar.  The most "off the wall" approach to catching them was when my buddy George Fryk found some fruit flies circling a piece of over-the-hill fruit. He got out his vac, attached the wand to the hose, placed some fine cloth (cheese cloth?) over the wand opening and pushed some of the material into that opening. He vacuumed the flies, grabbed the ends of the cloth, tied it shut and whipped it into the freezer for 15 minutes. The flies were most accommodating after that point.

I don’t raise them, but have seen people with mostly homemade bottles, plugs, and culture media. All of those can also be purchased. The hatching flies need something to climb out on. A couple of those raising flies around here use a ½ inch wide strip of that plastic rug mesh. (1 cm will do fine.) You can almost hear them singing. “We Are Climbing Jacob’s Ladder.”

Some hobbyists would rather not feed the flies, which, as you pointed out, may not have functional wings, but they sure have legs! Those people remove the hatching medium from the larvae (which sounds better than maggots, even though they are pretty clean.) After the, probably even more nutritious, larvae are rinsed, they are placed in clean water and carefully fed to the fish with a turkey baster. They are usually well received. I would look to see if guppies can handle D. melanogaster maggots before really getting into their production. Here are a few of the sites I have had mentioned to me, plus a couple of Googled ones which sound promising.

Instructions:
http://www.a1reptiles.com/a1ffcare.html
http://fins.actwin.com/search.cgi

Fruit fly media recipes:

http://www.edsflymeat.com/media.htm (hydei medium)
http://www.thelabrat.com/protocols/FruitFlyMedia.shtml

Commercial sources
http://www.joshsfrogs.com/catalog/product_info.php?cPath=21&products_id=36
www.blackjungle.com
http://www.livefoodcultures.com/