Preventing Fruit Fly Cultures From Crashing

We have all been there. One day your Fruit fly culture is booming and so full of flies, and the next day they are all dead. You ask yourself how did this happen. Well there are several possible reasons why a fruit fly culture may crash. Here are some of the most common reasons crashes happen, and some solutions to prevent your next fruit fly culture from crashing.

Cash caused by Overheating (or over cooling)

During the summer months, the most common reason for a fruit fly culture to crash is due to overheating (or over cooling). The Ideal temperature for D. Melanogaster and D. Hydei is between 16 °C to 29 °C. Anything much more below or above the Drosophila ideal temperature range will be fatal.  Your frog room shouldn’t be reaching temperatures of over 29 °C for the health of your Dart Frog.

Some solutions to prevent overheating your fruit fly cultures

Installing an air conditioner unit in the room. You don’t have to spend a lot of money on one. You just need to regulate the temperature of the room. At Jungle Jewel Exotics we keep our Frog Room at approximately 24°C. Be careful not to place fruit flies, Dart Frogs or Vivarium’s to close to an Air Conditioner, as it will freeze them.

If your frog room is at a comfortable temperature, but you are still having crashes or poor production try moving your fruit fly cultures to a lower shelf or onto the floor. A normal room will vary in temperature by a couple degrees, and may be cooler near the floor.

Try converting part of your basement Man Cave into a Frog Cave. A basement can regulate temperature much better than any other area of the home. For many people, they have had the most success with building a frog room in their basement. For others this may be a temporary arrangement for the summer months.

During the winter months be careful not to place fruit flies or Vivariums with Dart Frogs directly over a heating vent, as this may also be fatal. You must also be wary of placement near a drafty window or a very cold exterior wall for the same reasons.

Over population

Another very common reason your fruit fly culture may crash is due to over population.  When making your fruit fly culture, make sure you use some sort of material to give the newly hatch flies a place to rest. Some common materials used may be coffee filters, plastic bags, mesh material, Excelsior packing material. There needs to be enough space in you fruit fly culture so they are not crawling over each other. This will result in too much stress and may cause a culture crash. Secondly with over population it also raises the temperature of your fruit fly culture, resulting in a crash due to overheating.

To dry or to wet

It is common in the winter months for your fruit fly culture to dry out. This will result in low production or a culture crash. It is caused by the low humidity from the outside air, and compounded by dry air being heated by your furnace.  You can help this, by making your new cultures with a little more water at the beginning. However be careful not to add too much, as a soupy mixture will drown the eggs and larva of the fruit fly. If you notice your culture is drying out, you can add a few drops of water to keep it hydrated. A better solution is to place your fruit fly cultures in Tupperware containers or Tote bins to help regulate the humidity. Be careful not to place the bin to near a heating vent as this will cause your fruit fly cultures to overheat.

CO2 gassing

Sometimes a fruit fly culture crashes before it can begin. In many fruit fly culture media recipes, yeast is used as a form of food for adult flies and added protein for the larva. If you are using a live Baker’s yeast in your home made recipe please allow 24 hours for your culture to release the CO2 gas before adding new flies. Many commercially made fruit fly media use a Brewer’s yeast as it is not alive, and doesn’t give off CO2 gas.


A moldy culture is not a healthy culture for fruit flies. If you’re using a commercially made fruit fly culturing media, they have worked the bugs out for you (no pun intended) However many people decide to make a homemade mixture to save on cost. It is very common for a homemade fruit fly culture media to go moldy.  Methylparaben is a commonly used ingredient in commercially made media as a mold inhibitor. However methylparaben has an estrogenic effect, and can cause lower population sizes in your culture. At Jungle Jewel Exotics we use a homemade recipe that utilizes vinegar for its anti-fungal properties. We have tried several commercially made fruit fly medias and agree that they make great product that is easy to use. However we find that we are able to produce more flies using less media then their media using a recipe that contains no methylparaben.


The bane of every Frog keeper that makes fruit fly cultures is mites.  These tiny little arthropod compete for food and can kill the fruit flies. You’ll know you have mites infesting your culture as your face and skin will suddenly feel itchy and crawling when you open a fruit fly culture to feed it to your frogs.  Not to fear as they are harmless to humans, just uncomfortable. You can easily remove them from your body by washing with soap and water. The mites are harmless to your Dart frogs as well. However mites can be disastrous and sometimes fatal for your fruit fly culture. If you discover a mite infestation in a fly culture it is recommended you dispose of that culture immediately.  Never start a new fly culture from a mite infested culture. If you reuse your old fruit fly culture containers and lids make sure to wash them thoroughly in a normal bleach dilution or freeze them for a day. This will help reduce further contamination. Mite reproduction time is a little longer then the D. Hydie life cycle. As such if you are diligent about disposing old cultures before 30days you may stay a bit ahead of the mite infestation. Also when seeding your new fruit fly cultures only select from freshly hatched cultures as this will buy you some more time. Another trick we try at Jungle Jewel Exotics is place a few granules of garlic powder in our media. It helps weaken the exoskeleton of the mites resulting in lower populations and seems to be harmless to the fruit flies. Another method practiced by some frog keepers is to use a mite paper. This is a paper with a mild insecticide on it. If used diligently it can help prevent the spread of mites from one culture to the next. Some people are experimenting with diatomaceous earth as this also weakens the exoskeleton of the mites and may result in death for the mite.

We hope these tips will help you in the future in preventing a fruit fly culture crash. If you have any tips or suggestions we would love to hear about them in the comment section below.

Happy Frogging


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