Wingless fruit flies are appreciated by a wide range of fish, especially those who would feed on small insects on the water’s surface in their natural environment. Fruit fly is for instance an ideal food for pencilfish and hatchetfish. Growing your wingless fruit flies at home is not very complicated and you will always have suitable live food ready for your fish devour.
To being with, you naturally have to obtain wingless fruit flies. You can for instance purchase them from an aquarium shop or ask your local fish club if anyone is willing to sell or donate flies.
You will also need some type of ventilated container to house your fruit fly culture. A one quart (or 1 litre) fruit jar or sealer is handy, but virtually any type of container will work, as long as it has a fitting ring. A glass container is recommended since glass can be boiled prior to use, thereby ensuring clean conditions. You will also need a piece of clean cloth.
The next step is a create something that allows your wingless fruit flies to get out of the culture medium. You can for instance use Popsicle sticks or a peace of cardboard or even better use a peace of that plastic mesh sold in needlework shops. What ever you decide to use, it should go from the bottom of your container up to near the top.
The fourth step is to get food for your wingless fruit flies. If you look in your own kitchen, you will probably find a lot of suitable foods. One popular fruit fly food recipe contains potato flakes (the type used for ready-made mashed potatoes), corn flour, brewers yeast, granulated sugar, and apple cider vinegar. Mix ½ cup of potato flakes with 4 teaspoons of corn flour, 2 teaspoons of brewers yeast and ½ teaspoon of sugar. Gradually stir in apple cider vinegar until the mixture turns into a smooth paste. Never use water instead of apple cider vinegar since this type of mixture easily becomes infested with mould without the acidic vinegar. This recipe is enough for two 1-litre containers, unless they are really shallow with broad bottoms.
Make sure that the container is perfectly clean by boiling it. When it has cooled off, add the potato flake medium to the bottom of the jar; it should be roughly ¾ of an inch. Put the “ladder” (popsicles or similar) in place. Add roughly 30 wingless fruit flies to the container.
Place a piece of cloth over the top of the container and screw on the ring. It might be tempting to use a plastic lid and simply punch a few breathing holes in it, but keep in mind that winged fruit flies are small enough to fly through such holes and take over the colony. This is not a catastrophe since most fishes will eat flying fruit flies as well with gusto, but most aquarists find the windless ones more convenient.
After a few days, you will be able to see tiny maggots crawling at the sides of the container. As they develop, they will eventually turn into pupae. Once they have become pupae, it will take a few additional days before they are fully developed fruit flies. The exact time will depend on the temperature inside your container. If the temperature is ideal and the culture is kept moist, the entire process can take less than two weeks.