Culturing Blackworms from a Single Worm

Michael Langerman
8 min readSep 7, 2021

You can buy Blackworms on Amazon:

I have has a colony of Blackworms in this 1.6 liter sustainable aquarium garden for about 9 months so far.

Let’s pull some Blackworms out to take a look.

Blackworms reproduce by fragmentation.

They also can reproduce by laying eggs.

Though, I’ve never seen eggs of Blackworms to tell you anything about it for sure.

Reproduction by fragmentation is an amazing ability of Blackworms we can use to grow a colony from a single worm.

For the purpose of demonstrating this, I am going to use this 16oz plastic container to make a nursery.

Fill it with dechlorinated water.

Here I use water from another aquarium garden.

Now let’s cut one Blackworm in two.

I cut the worm somewhere in the middle.

Here you can see both parts of one Blackworm.

Let’s put both parts in the nursery.

All aquariums, including this nursery, need live plants.

I add a cutting of Guppy grass.

Also, you may notice some Seed shrimp get in the nursery.

So, here I have both parts of one Blackworm with Seed shrimp and Guppy grass.

Both parts of the worm move independently regardless of which one is head or tail.

Now I add some green algae water for Seed shrimp.

And let’s add a small pinch of fish food flakes.

Cover the nursery with a lid.

The lid has a hole to allow air circulation while reducing water evaporation.

I set it up on May 30th, 2021

Two weeks later on June 14th.

You can see both parts of the Blackworm are alive and actively moving around.

There is a lot of green algae on the walls and bottom of the container.

I feed Blackworms with a small pinch of fish food flakes twice a week.

It takes time for flakes to sink down to where blackworms will consume them.

June 29th.

One month since I split one Blackworm in two parts.

Both parts should have already regenerated the missing parts of their bodies.

Let’s pull both Blackworms out.

There are a lot of Seed shrimp and…a baby Blackworm!

Well, the baby worm is actually a fragment of an adult worm.

Let me get the other one.

Here it is.

So, one month ago I split one Blackworm in two parts and now I have three worms.

Apparently, one of the parts started fragmentation on its own.

Now I can split each adult worm in two parts doubling the amount of worms in my nursery.

I split the worm on parts just as an example.

Adult Blackworms break into parts naturally.

It is the way Blackworms propagate or breed.

Fragmentating is a way to survive for Blackworms when fish tries to eat them.

We can enforce Blackworms fragmentation either by cutting them or providing them with obstacles.

Gravel, rocks, and seashells are great obstacles for Blackworms to fragment by climbing around.

Here I feed them with dry Guppy grass.

I keep this nursery on a shelf with my aquariums next to a window away from direct sunlight.

Two months later on August 30th.

Let’s scoop some samples from the bottom of the nursery.

You can see Blackworms wriggle in the dirt here.

The colony of Blackworms started from one worm grows, doubling every month or so.

So by end of the 3rd month there should be about a dozen of Blackworms or so.

Leave them alone in this nursery, there would two dozens of worms by end of the next month.

The number would double every following month until the colony reaches the capacity of the tank.

The larger the container, the more Blackworms may grow in it.

I grow Blackworms only to feed them to my fish.

So, the next logical step is to put all these Blackworms into an aquarium with fish.

Here is one of my 1 gallon sustainable aquarium garden with dwarf guppies.

The Blackworms with Seed shrimp and algae go all together into this aquarium.

Blackworms will find plenty of fish food to feed on and gravel to hide in this aquarium.

The space of this tank allows for the colony of Blackworms to grow.

And it will provide live Blackworms for my fish to feed on.

That is the beauty of sustainable aquarium gardens — no efforts on my part!

No water changes, no man made filters, no noisy pumps, and the fish food growth right here.

Also, I still have the small container with a colony of Blackworms :)

And it is all from one Blackworm!

Have fun and happy aquarium gardens :)