Earthworm vs Flatworm – What’s the Difference? (and do flatworms eat earthworms?)

If you’re considering putting earthworms and flatworms together, make sure to take a different route. Believe it or not, these complex animals do not get on!

Simply put, in the earthworm vs flatworm fight, the earthworm usually does not come out on top. These two types of invertebrates are incompatible.

Over the years, some native flatworms have been joined by their overseas cousins. Especially invasive, those finding a way to the west from Australia and New Zealand are particularly ferocious predators.

Let’s also take the time to consider these different species in a bit closer detail – what sets them apart?

What is difference between flatworms and earthworms?

The earthworm lives in the ground and actually, worms feed on soil and the nutrients within. Free-living flatworms, however, are parasites, acting almost like leeches that feed on other worms and other species.

Their ravenous hunger results in sometimes drastic changes to the ecosystem.

An earthworm and a flatworm have a different body structure, too.

Earthworms have a mouth, a tube-like body and they are segmented worms with circular muscles.

They eat from a mouth at one end of their body and expel the waste matter from the posterior end, meaning that they have a complete digestive tract.

Flatworms are not complex animals, as they have only a single opening from which they eat and expel waste. This means that they have a different digestive tract from general worms.

In other words, they have no separate anus. It is therefore not considered to be a complete digestive system.

They do not have a body cavity either. As their longitudinal muscles contract, this makes them appear smaller and wider and helps with their movement.

Their life cycle is also different as flatworms only live between 60 to one 140 days, whereas other worms can live for years and years.

However, the parasitic flatworms do have the same respiratory system as the earthworm, in that they breathe through their skin.

On the other hand, they don’t have anything as sophisticated as a circulatory system, a nervous system or blood vessels – in fact, they are almost completely devoid of organ systems.

However, they are thought to have some receptors that help them feel, just as nerve cells might.

Do flatworms eat earthworms?

Yes. flatworms are predators, and they get their nutrients from other living organisms in the dirt, including segmented worms.

The population of worms in some areas has become dramatically reduced as hungry flatworms have wiped them out!

Therefore, if you are considering mixing the two together, don’t.

The flatworm is a parasitic animal that won’t just cause problems for your earthworms, but for other wrigglers you might have in the soil and compost, too.

Earthworms, on the other hand, won’t eat flatworms. In. fact, they won’t eat anything that’s not dead or decaying.

Therefore, this really is a one-sided fight that you’re going to need to help your earthworms to escape.

earthworm scared of being eaten by a flatworm

How do flatworms eat earthworms?

The way flatworms eat earthworms is fairly gross, so skip this section if you’re eating dinner.

Flatworms are, by and large, covered in slime.

On finding their prey (any kind of worm, for example), they cover this secretion over the body of their victim. The prey is effectively dissolved in the slime and subsequently eaten.

There’s preparing a meal – and then there’s following a flatworm. Don’t subject your earthworm farm to this kind of end.

Are earthworms better for composing?

Yes, they are ideal for composting. Soil which is well inhabited by earthworms has a rich, soft grainy feel and can range in colour from reddish-brown to deep black.

A poor quality of dirt can be an early indicator of a lack of worms. Research discovered that a severe decline in earthworm populations has had a severe derogatory effect on crops in Scotland, for example.

Therefore, it’s all the more reason for making sure you look after your worm bin.

Disease control is important for one thing – but there are going to be invasive species like flatworms who are ready and waiting to take advantage of your favorite wigglers.


Flatworms and earthworms are extremely different species. Many will see the parasitic flatworm to be a pest, while earthworms and wigglers are genuinely helpful to our gardens and worm bins.

Take it from us – while worms are not the most complex animals on the planet, that doesn’t mean they can be left to their own devices.