Microworms Info

Gills and Fins – your source for live microworm cultures and information.

Worm Size: Microworm adults can get up to ⅛” long. The baby microworms are much smaller, so you will get a rage of edible food sizes for your fry.

Microworms Culture
Microworms Culture

Microworm Nutrition: Protein 48%, Lipids 21%, Glycogen 7%, Organic Acids 1%, Nucleic Acid 1%


Media: Microworms multiply like crazy and are very easy to culture. The media can be a few different things, but we use  Instant potatoes, water, and dry active yeast mixed up like a smooth mashed potato mix, then sprinkle the yeast over the top.


Start: Add a glob of microworms from the culture you got from us. The worms do the rest. In a few days, they will start crawling the sides of your container for you to harvest.


Formula:  There is no magic formula to culturing microworms. Some use oatmeal, some use baby food and some you instant oatmeal.  From trial and error and shipping them over the years we have found that instant potatoes work as well as the others if not better and smell so much less.  The oatmeal mix smells so bad we would never use it.


Set-up: Setting up your culture is extremely easy.  Start with about ¼ to ½” instant potatoes add dechlorinated or R.O water and mix until it’s a smooth mix. Next, add your starter culture and spread it over the potatoes, then sprinkle with the dry active yeast.  That’s it!!

Microworms Supplies needed
Microworms Supplies

Containers: You can use anything with a side of at least 2-3”. Rubbermaid sandwich containers work well or other Rubbermaid storage containers with a lid. If you want to raise large amounts of microworms a shoebox-sized container works well too. You just want to make sure it has a tight-fitting lid to keep out pests and keep the microworms in. We have had cultures climb the sides of containers about 4-5”.


Cover Your Container: Microworms need a lid for several reasons. It helps keep humidity enough for them to crawl the sides. Covers keep out pests and keep your microworms from escaping if they climb too high.  You do want to make sure your culture can breathe, so make sure you make a hole and plug it with foam or filter floss. That will keep pests out and let fresh air in.  Your culture will also need a vent to let out the carbon dioxide that comes from the yeast.


Smell: Healthy new cultures will have a pretty good smell, something like fresh bread and as the culture ages the smell will start to get a little sour. We have found that potatoes smell far less than oatmeal. As oatmeal cultures get old it smells like poop, so we choose not to use oatmeal. We like the smell of fresh bread much better.


Recharging Cultures: Since it’s so easy to start a new culture, most people want to recharge an old culture, but there are some good reasons to recharge your culture. If you let your culture sit too long or your culture just gets run down by ignoring it, you may need to recharge it. Just sprinkle it with a little more yeast. You can even go as far as adding more potatoes if it’s getting a little too runny. The instant potatoes will suck up some of the extra moisture and thicken up your mix, then just sprinkle with a little yeast and your culture will get a little jump-start. If even two worms survive that’s enough to start a new culture.


Harvesting: The easiest way to harvest worms is to wipe them off the sides of the container with your finger. Or use a tiny rubber spatula if you don’t want to touch them with your finger. Then just feed them to your fry. Rinse your finger in the tank or a cup of tank water then add them to the aquarium with an eyedropper. You don’t need to worry about getting any of the media in your tank it’s just potatoes and the fish will eat that too. Some fish foods actually use potatoes as an ingredient.


Microworms Sink: Microworms wiggle and attract your fry, but they can’t swim. They will float to the bottom being eaten as they fall. This means you should keep your fry in bare bottom aquariums if possible. Microworms will wiggle on the bottom for several days while being eaten by your fry. Our baby Corydoras love eating microworms off the bottom as well as our Angelfish fry.


First food: We do not use Brine shrimp at all in any of our fish rooms it’s just too much work. We use Microworms and Vinegar Eels as first foods and graduate the fry to Grindal worms. We will supplement with a good quality flake food too. You want to make sure your fish get all the vitamins and minerals they need. Microworms work extremely well for even the smallest of fry, such as betta fry. We do use microworms for all of our fry.  Get yours at our shop by clicking here and check out our DIY Cultures for more info and videos by clicking here.