How do I Make a Fruit Fly Culture?



Fruit flies are one of the easiest feeder insects to care for. Each 32 oz fruit fly culture includes all the food and water the flies will need for months. The culture will continue to produce flies for at least 2 months. Freshly Started Hydei Cultures will start to produce flies you can feed to your animals in 17-21 days. Freshly Started Melanogaster Cultures will start producing flies in 10-14 days. Each culture has the potential to produce 1000s of flies, but there are a few things that can slow down or stop production all together.


Fruit fly cultures are prone to dry out in environments that are under 65% humidity. To maintain humidity, place the culture inside of a clear Rubbermaid container or storage shelving unit to keep the culture from drying out. You can also spray down the culture with de-chlorinated water if it dries out.


Fruit fly cultures should be kept between 70 and 80 degrees. If the cultures hit 85 degrees even for a little while, the culture will go sterile and will not produce any more flies. Cultures that are kept under 70 degrees produce much slower.


Our 32 oz fruit fly cultures are made with a media that has a mold inhibitor already in it. However, if the culture begins to dry out, mold will appear on the top of the media. If mold develops on the top of the media, spray the mold down with some de-chlorinated water and put the culture in a clear Rubbermaid container or storage shelving unit to maintain humidity.

Mold will occasionally develop on the coffee filters or excelsior used in the culture. To prevent this from happening, make sure cultures are away from heater/air conditioner vents. If mold develops on the coffee filters or excelsior used in the culture, remove the portion with the mold on it before starting new cultures from that culture to avoid spreading the mold. Feeding from a moldy culture will not hurt your animals.


Mites are tiny bugs that love to attack fruit fly cultures. Mites are everywhere, so care must be taken to prevent mites from taking over your cultures. All cultures should be placed on paper towels that are sprayed with a Mite Spray. In addition, the area where the fruit flies are stored should be cleaned regularly. There are mites in all fruit fly cultures. These mites are feeding on the media, and do not cause problems unless cultures are kept improperly.



1. Fruit Fly container and lid

2. Fruit Fly medium

3. Water free from Chlorine – Chlorine will slow the rate of fruit fly production. You can use distilled, RO, spring, etc.

4. Active Baker’s Yeast

5. Coffee Filters or Excelsior - Needed to create more surface area for more flies.


1. Heat up 1/2 cup to 1 cup of chlorine free water per culture. Make sure the water is boiling, as the mold inhibitor will not be effective if the water is not warm enough.

2. Add 1/2 cup of Josh's Frogs Fruit Fly Media to each 32oz Fruit Fly Culturing Cup. Josh's Frogs Fruit Fly Media has a mold inhibitor already in it, so do not add vinegar, etc.


3. Add 2/3 cup hot chlorine free water to cup. Stirring or mixing the media and water is not needed. Future fruit fly larvae will do it for you! When your cultures start producing, observe the consistency of the media. If it is too runny, add less water when you make your next cultures. If the media dries out, add more water next time.


4. Wait until the moist media has cooled to room temperature. If you do not wait, the higher temperature can kill any activated yeast or flies you add. If you are in a hurry, you can put the culture in the fridge for 5 minutes. Make sure the culture is covered, so that wild fruit flies and other pests do not get into the culture.


5. OPTIONAL - Sprinkle a pinch of Active Yeast on the surface of the media. Active yeast will grow in the culture and outcompete harmful molds that can grow in a fruit fly culture. Currently, Josh's Frogs provides yeast with melanogaster media. Yeast is not needed for hydei cultures, as the larvae keep the media churned and mold is generally not an issue. If you are using flies from us, or a culture that contains yeast, the flies added to the new culture will bring yeast spores with them on their feet, making the addition of active yeast unnecessary.

6. Place a handful of excelsior in the fruit fly culture. Surface area, in the form of excelsior or coffee filters, provides a place for flies to crawl, mate, and lay their eggs. Josh's Frogs sells and recommends excelsior, as it allows more flies to be produced in a culture.


7. Add 50-100 Fruit Flies. For melanogaster cultures, we recommend using flies from cultures that are just starting to produce. For hydei cultures, use flies from a newly producing culture and flies from a culture that has been producing for 1-2 weeks. Dust the flies with a calcium supplement to remove hitchhiking mites and to make the flies easier to handle.


8. Immediately put a vented insect cup lid on your culture. Be quick - you don't want fruit flies everywhere!


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