Wingless vs. Flightless

A major difference between the regular and the hydei varieties of FF (besides their size) is the gestation. The larger variety takes a month to complete the cycle where the little ones, as few as 14 days. 

No matter what you call them or their scientific names, for the general purposes of raising a live food, fruit flies are cultivated the same way. So rather than have to use all of the words...we're just going to call them FF.

We use commercial media to raise our FF in. We are not lazy, it's just a bother to mix up home-made pasty concoctions. Then with the home made concoctions you will find mold to be a significant concern. To take care of the mold you would have to consider using chemicals to treat the concoction. We just find that ordering the stuff from a vendor is better for us. You might make a different finding. We carry a good quality food mix that's easy to use and produces great results...

The easiest bottle to raise these critters in is a water bottle such that one of your favorite spring waters might come in. We use pint sized (500 ml) units. We like the plastic ones (you will drop one some day). We plug the tops with a piece of sponge. The sponge allows for air transfer. When you use sponges be sure that the sponge is not a "disinfected" one that is designed for kitchen or bath use. Recently we have started putting a small amount of plastic netting into the culture prior to adding the media. The FF seem to be doing better with the netting. 

The media is mixed in a 1:1 ration. We put 1/4 cup of media in the bottle and then 1/4 cup of water. A pinch of Fleischmann's yeast and wait five minutes or so for the mixture to completely solidify. Add the netting and your FF culture and put the sponge in the top. Of course you can always mix your own medium...
A major difference between the regular and the hydei varieties of FF (besides their size) is the gestation. The larger variety takes a month to complete the cycle where the little ones, as few as 14 days.  

Harvesting is a little tricky. Sharply tap the bottom of the container in the palm of your hand and then pull out the stopper. Shake a few or perhaps tap on the container to knock a few flies out onto the water of the tank. Put the stopper back into the culture bottle. We find that after a while the fish will come to the surface when they hear the tapping on the palm of the hand, even when you are feeding the tank next door. We find that 6-8 flies per fish per feeding is an ample rule of thumb. A few less for smaller fish and a few more for larger ones.  Like any food, too many flies and they will not be eaten. While the surface tension of the water will keep the vast majority of flies in the tank, occasionally you will find a FF wandering near the tanks. Fruit flies can escape from the water tension and crawl out of the tank. We don't find this to be a problem as it is generally only a fly here and there, not like an army of them...oh and our tanks are not in our living room.

We start new cultures each week. The cultures will become less productive in a month to eight weeks. The media will go bad a couple weeks later becoming black and offering little in the way of food for the larvae. Don't  wait until the media is bad to start a new culture. Beware that heat will kill the flies. You want them to be warm but not extremely hot. Heat may leave the maggots behind and you can save the culture, but why take the chance? We keep our flies at a comfortable room temperature.