Problem with my 1st Fruit Fly culture

Elliott-the-Mantis · Aug 23, 2020

A few days ago I bought all the bits for my first fruit fly culture, Wood wool, Potato flakes, Yeast, Vinegar.

I used half cup potato flakes, half cup of water, 2 tablespoons of vinegar and a pinch of yeast.

Its been about 4 days, I put around 20 flies in there and I have already got mold growing at the bottom on the potato mixture

, Is there anyway to rectify this or should i just rescue the flies and bin the mixture? Has anyone got a recipe were this will not happen? What did I do wrong?

Thanks Elliott.

Synapze · Aug 23, 2020

How much mold? Sometimes mold forms, but if it doesn't get too bad the flies and larvae will eat it (I'm guessing) since it often goes away.

What type of yeast do you use? What is the consistency of the media?

Elliott-the-Mantis · Aug 23, 2020

Just a tiny bit of blue mold like what you get on bread, I used a pinch of yeast and the consistency is just like mash potato, not sticky at all, Just kind of dry? and I used bakers yeast.

Synapze · Aug 23, 2020

You can give it a little spritz with purified water if the media looks too dry. When it comes to mold, I've had better success with brewer's yeast. If it's just a little mold, I wouldn't worry about it. You may want to consider using a few more flies than 20 to start a culture. I usually put in about 50. If the mold gets bad, don't use the flies from that culture to establish another or you may risk contaminating the new culture.

Here's a recipe I've had luck with.

I've been using a recipe that was suggested to me by @ausar318

7 parts cheap unflavored potato flakes

1 part confectioners sugar

1 part brewer's yeast

1 tbsp white vinegar

1 tbsp apple cider vinegar

I add cinnamon as well... seems to keep odor down.

I mix a large batch of the dry ingredients together and grind into a fine powder and store in the freezer until needed. When I make my cultures I put the vinegar in and add boiling purified water. Tada.