- A Plastic Container With a Top (Margarine Containers are Great for This).
- Pure Oatmeal
- Dry Yeast
- Microworm starter culture
If you’re serious about breeding fish, then at some point you should consider starting a culture of microworms. These tiny worms are the perfect food for many species of newborn fry and their wiggling motion in the water triggers a fishes hunting instinct. If you don’t offer newborn fry a source of live food, you will often have a very high mortality rate among the fry.
These tiny worms are actually a nematode, and they grow up to around 0.1 inch (3mm) in length. They have a whitish color to them and most will clump together in long strands of worm in the culture. Each culture will hold hundreds or even thousands of microworms, and you can easily see them climbing the sides of the cointainer that they are kept in.
What makes microworms one of the best cultures for fish is that once you have the culture going, they are incredibly easy to maintain and only need maintenance every few weeks. This is in sharp contrast to Daphnia and blackworms which need constant attention and often crash for no reason. A single culture of microworms can easily last for 4 weeks before it needs to be changed, though I would recommend that you keep several cultures going in case of unexpected crashes.
Getting Started
To begin with, thoroughly clean out the plastic container that you are planning to keep the microworms in. Make sure that there is no soap residue, and that is has been rinsed in water several times before adding anything to the container. At this time you should also add some air holes to the cover, but keep them as small as possible to help keep pest insects out.
After the container has been prepared, you should add about ½ inch (1.2 cm) to ¾ inch (1.9 cm) of dry, plain oatmeal to the bottom. Then add some water to the oatmeal, making sure that the oats are damp, but not watery. Thoroughly mix it together so that all of the oats are wet, making sure that there is no excess water.
Once you are satisfied that the oats are damp all the way through, you should add a small amount of yeast to the top of the oatmeal. It’s better to err on the side of caution and add too little, rather than too much, and you really don’t need much in the way of yeast to start with.
After you’ve done that, you’re ready to add the microworm culture to the container. The microworms are usually pretty easy to pick out, and their coloring seems to almost shimmer under a light. Use something soft like a Q-tip or paint brush to move them, since anything hard will likely injure or kill them.
Very softly spread the microworms over the top of the culture, and this is where it’s very important that it’s not too wet. You want them resting on the top of the culture, and not sinking into it. After the starter culture has been added, you should immediately cover it. Pest insects like fruit flies can become a major problem for microworm cultures, and a way around this is to fill any air holes with cotton or something similar that will still allow air in the culture, but keep the pests out.
Within a few days, you should start to see hordes or tiny microworms scaling the sides of your culture. It’s at this point that you can start harvesting them, and it’s as simple as wiping them off the side with a finger and placing them in your aquarium. I tend to use glove for this, but it’s up to you how you want to do it.
After about 4 weeks, the culture will start to smell. This is the signal that the culture needs to be replaced, as you won’t be able to keep it healthy beyond this point. To create a new culture, just replicate everything listed above, and transfer some of your existing microworms to your new culture.
Most cultures will do well at room temperature, and seem to do better in a well lit room. Never let a culture fall below 32 degrees, and they should be kept somewhere between 70-85ºF (21-29ºC) optimally. I’d also like to stress that you should always keep multiple cultures going, since crashes while rare, are not unheard of. And if you’re culture crashes and you only have the one, then you’ll have to track down another starter culture.
Jackie Peschong says
Rob, I just started reading your site. So much info. Thanks. Do pet shops have micro worms so that I can start my own cultures? Will goldfish benefit from micro worms as well as tropical fish? Thanks.
Robert Brand says
Hey Jackie,
I’m glad that you’re enjoying the site. Most pet stores do not carry microworms, but many people keep cultures going in their houses and they are usually pretty happy to share them. I was able to get mine by posting on a local aquarium forum, and someone near me gave me a starter culture for free.
And they are really only good for small fish. If you have adult goldfish, they will probably be too large to even bother eating them. But small fish like neons and guppies still enjoy them well into adulthood.
Jackie Peschong says
Very helpful, Rob. Thanks. I look forward to more interesting information. Thanks.
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Karen says
Heyyy… this is a very good site too see, i wanna ask you something ; after those worms start smelling we make another culture and scrape of the worms that are in the sides… then what do we do to the other worms and its culture? Please respond.. tq
Robert Brand says
Most of the time the easiest thing is to feed as many as you can to the fish, and then toss the culture. Alternatively, you can wash the culture out and start over again, but that’s often a pretty messy and unpleasant thing to do.
Hezo says
Do you have to use a starter culture
Robert Brand says
Unfortunately, you do need to find someone with a microworm culture to get started.
Philip says
do you need light for the culture? Thanks!
Robert Brand says
My understanding is that they don’t need light, but I’ve always kept them in room with natural light. No additional light needs to be provided for them.