There are several species of fruit flies, but it is easier to categorize them as wingless and flightless. Wingless don’t have any wings or have small clumps of wing material, as where flightless have wings, there just not able to use them.
All species of Fruit Flies are raised the same way. There is commercial media available to raise them in, or you can make your own, both will need you to use active yeast. The benefit of the commercial media is that it already has a mold inhibitor mixed in it, no need to measure out the proper dosage. There are also a few homemade recipes one of which I will include at the end.
It is easiest to bottle raise these. For that you can get a small water bottle and place the media in the bottom, approximately ½” deep. Any more and it will be a waste. You will need something for them to climb up to get out of the media. I use those plastic canvas sheets that are used for needlepoint. You can also use excelsior (make sure it contains no dye). Both of these are readily available at a local craft store. You will also need to make a foam stopper for the top of the bottle. This will keep the fruit flies in, and unwanted critters out. I use soft foam cut small enough to fit in the neck of the bottle. You can also use a sponge just make sure it has not been treated with anything. After you have done this add a starter culture, usually 20-25 fruit flies. If you put them in the fridge for about 15-20 minutes it will slow them down enough to make it easier to add them to into your new culture bottle. In about 2-3 weeks you will notice little things crawling up the sides, they are the maggots that will eventually turn into the fruit flies. I find it best to keep the temperature between 65-72 degrees. For some reason if they are kept at higher temperatures they grow wings that they can use, and are able to fly. If this happens just open the bottle outside and let the ones that can fly out.
Harvesting these can be a little tricky. The best way I have found that works, is to sharply tap the bottle, which will knock a lot of them off of what they are perched on. I find if you use the plastic canvas it is easier to harvest and clean up for your next batch. Then just dump a few into your tank. Sooner or later you fish will learn to recognize the sound of you thumping the bottle, and come up begging to be fed.
It is best to start a new culture regularly. This is so one doesn’t foul and crash, usually once every week or two. I have 6 cultures going on at all times. This will ensure you have enough to feed your fish without depleting your cultures.
I regularly use commercially available culture media. It saves time and money in some cases. But I have also used a “home brew” which I found on the internet a while ago. I forgot where I found it, but it seems to work great. There are a lot of other recipes available. Try out a few and decide which works best for you.
Here is the recipe I use.
Home Made Culture Recipe:
½ Cup Instant Mashed Potato flakes.
4 tsp. Cornflower.
2 tsp. Active yeast.
½ tsp. Sugar.
Apple Cider Vinegar.
I mix all the dry in a larger portion and when needed add in the Apple Cider Vinegar before I use this. The Apple Cider Vinegar has 2 uses, first it is a good mold inhibitor, and second it helps bind the items together. When ready to mix the dry with the Vinegar you will want to mix it in a 1:1 ratio, it will be the consistency of a dry paste. You don’t want it to be too wet, or it will foul your culture.