Microworm Care Sheet

|   Microworms (panagrellus Redivivus) Microworm Background: Panagrellus Redivivus or Microworm is Actually Not a Worm at All, but Called a Worm Because of Their Minute Size and Worm Like Appearance. Microworms…

Microworms (Panagrellus redivivus)

Microworm Background:

Panagrellus redivivus or microworm is actually not a worm at all, but called a worm because of their minute size and worm like appearance. Microworms are actually a species of nematode, which grows on average to 1.5mm or 1/16 of an inch. This is very tiny, and if you can’t see very close you might just miss them. Microworms are white-clear and have a worm like shape and movement. Microworms are non-parasitic and live off of the bacteria and yeast from the culture medium. They live for about 20-25 days and a female microworm can have 300 young in her life time. Microworms can live at temperature below 32F degrees, but optimum reproduction rate is at about 68-85F degrees.

Why Microworms?

Microworms are one of the best foods to start out for your newly hatched fish fry like killifish, guppies, betas, gouramis, tetra, barbs, danios, and many others. They are more size appropriate (1/16 inch) for very small fry that are not able to eat baby brine shrimp. Baby brine shrimp are often too large for some newly hatched fish fry to eat in the first couple weeks of life. Also, baby brine shrimp are harder to rear due to temperature, salinity, and growth restrains. Microworms are perfect for rearing at room temperatures. Also, you don’t have to worry about rinsing the salt off of your worms. Simply take your finger or a small clean paintbrush, and remove the worms from the sides of your container. Removing microworms from the sides will reduce debris contamination. Then, take your figure or small paintbrush, and rinse it in your fish tank. Remember over feeding of any food can cause a loose in a whole fry batch. The good thing about microworms is that they can live in a tank of water for over 12 hours. Microworms sink, and if you have given your newly hatched fry too much food, simply suck them out carefully with an eye dropper or turkey baster. Also, you don’t have to worry about microworms being able to growing too big for your new fish fry. Microworms are easy to culture at home for a never ending supple of newly hatched fry food. Microworms are made up of 76% water, and 24% Dry Matter of dry matter 40% is Protein and 20% is Fat. Remember a mixed combination diet for your fish is the best way to utilize your fish needs.

How to Culture Microworms

There are several ways to culture microworms. You just have to be able to meet their environmental needs. The container we provided for you, which your microworms are in, is only a temporary home for shipping purposes.

Firstly, you will need a container or two to hold you worms in. Plastic transparent containers work best. Like an old ice cream tub or deli container. The container must have a tight fitting lid. The container must be transparent because the microworms need light. Now, with the container lid you will need to puncture some small breathing holes in the lid (only lid.) Microworms need oxygen to survive, but now we need to keep out other pests from our microworm culture. It’s a fact microworms stink. But they are supposed to stink because they live and eat off of bacteria and yeast. But, this smell causes other creatures to want into your culture like flies. To keep the flies out, you need to either put a paper towel down under the lid when you close the container or you will need to tape a paper towel tightly over the holes you created in the top of your lid. Be careful not to tape your holes though. The towel will allow for air exchange, but keep pests out.

Now, you will need to prepare food for your microworms. There are several recipes that you can start your worms on and I will provide a couple that can work for home culturing purposes.

NOTE: Always allow your grain mixture to cool. Any hot temperatures will KILL your microworms.

  1. Oatmeal and baker’s yeast: Take any kind of oatmeal, but quick oats are the cheapest. Cook the oats on the stove top per makers’ direction, and go for a consistency of paste not too thin like soup and not to clumpy. Once, oatmeal is done cooking leave it to cool to room temperature. When the oatmeal is at room temperate, put it into your container. Next, take a little baker’s yeast just a tiny pinch and add it to the surface of the oatmeal. Now, it is ready to add your purchased microworm culture too. Take your worm culture and spread it on the surface of the oatmeal.
  2. Cornmeal and baker’s yeast: Take a box of cornmeal. Band I don’t think matters. Cook the cornmeal like you would oatmeal and looking for a paste consistency. Once, cornmeal is done absorbing the water and looks like paste, let the cornmeal cool to room temperatures. When the cornmeal is cool, add it to your container. Then, add a small pinch of baker’s yeast to the top. Now, it is ready for your microworms to be spread over the top.
  3. Baby cereal and baker’s yeast: Take any brand of baby cereal, and add it to your container. Baby cereal is already cooked and ready to use. Next, add water to get the consistency of paste. Next, add a small pinch of baker’s yeast. Now, it is ready for you to add your microworm culture to the top.

Don’t be hesitant. You can experiment and make your own culture food mixture too. The yeast in the mixture eats the grain, which helps to feed the microworms along with the natural bacteria present. You can take and divide the culture that we have shipped to you. Simply, divide in half any 1oz. culture into two parts and add them to a new container with food. A new culture will take anywhere from 3-7 days for harvesting. Harvesting times also depend on how big your new container and food supply are. The bigger the new container and food supply are the slower the begging harvest will be, but it will produce many more microworms. You can control how fast your culture reproduces by controlling the temperature. Lower temperatures allow the culture to last longer, but reproduction and harvesting are slower. Higher temperature, and your culture will reproduce faster and harvesting numbers are higher. Remember microworms are very small and you might just miss them if not able to see them up close. You will know when your microworm culture is doing well by look for them crawling up the walls.

When to Start a New Culture

You can expand your culture at any time after the culture establishes it’s self, usually after the initial 3-7 days. All you have to do is repeat the processes above. Otherwise, wait until your culture starts to smell really bad and has the consistency of runny soup. This is an indicator that all the grain is being used up by the yeast, and the microworm population is going to decline. At this point, you need to get a container again, add cooked grain, baker’s yeast, and repeat the steps stated above. If you keep your culture going, you will have a never ending supply of microworms for your newly hatched fry.


We always recommend never releasing live organisms into the environment. You should always use good hygiene practices with all cultures. Please wash your hands and materials after handling any culture.

Gifting or re-purposing a culture is always a good first option. But, if those options are unavailable you can follow these steps:

  • Make a 20% bleach solution (2 parts bleach, 8 parts water) fully submerge culture and container in 20% bleach solution for 10 minutes. Rinse and Drain culture, container and bleach solution down the drain until bleach smell has cleared. Dispose of containers and materials in garbage.
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