Perionyx excavatus, sometimes known as the Indian blue earthworm, is a native of South Asia, including Pakistan and Sri Lanka.
They can also be found further east in tropical climates like Malaysia (hence, sometimes being called “Malaysian Blues”) and as far as Australia.
They can grow in a variety of soil types and are typically found in tropical and subtropical areas.
They are also present in other regions of the world like North America, where human activities like trade, farming and gardening have introduced them into the habitat.
In tropical nations, they are frequently utilised in vermiculture (worm farming) and as a soil conditioner because they thrive in these conditions.
Additionally, due to their voracious appetite, they are often utilized in biowaste management to turn organic waste into vermicompost.
By the end of this page, every question you have about blue worms will be answered and you’ll no longer be in the dark when it comes to the famously shimmering (sometimes infamous) Indian blue worms – also known as Malaysian blues in some parts.
Indian Blue Worms Quick Fact Sheet
Size: Up to 3 Inches.
Ideal Habitat Temperature: Warm temperatures from around 70 to 80 degrees Fahrenheit.
Ideal Habitat Moisture: Around 70%.
Ideal Habitat pH: Neutral pH.
Scientific Name: Perionyx Excavatus.
Other Names: Malaysian blue or Indian blue worms.
Ideal Diet: Fruits, garden scraps, vegetables, cardboard, tree leaves, coffee grounds, and aged animal manure
Feed Rate: Consumes about a cup (240 ml.) of food in a week.
Reproduction Rate: Can produce 19 cocoons a week – with 1 worm per cocoon.
Days to Reach Adult Maturity: 21-35 days.
Composting Difficulty: Hard (lower tolerance for temperature, moisture and pressure changes).
How Do You Identify Blue Worms? Anatomy
As earlier mentioned, there are two scenarios where you can get confused about the identity of a blue worm – when turning up the soil in search of them or going to the market to buy them.
Whichever situation you may find yourself in, getting the right worm for your vermicomposting activity is essential.
You wouldn’t want to end up with a failed vermicomposting, right? Well to avoid that, check out how you can identify a blue worm when you set your eyes on one.
The first thing to look out for in a blue worm is its length.
Blue worms grow up to 3 inches when fully grown/stretched out.
To avoid mix-ups when buying blue worms or digging the soil for them you should put these two universal and important tips in mind;
1. Blue worms are longer and way thinner than red wrigglers.
2. Although longer than red wrigglers, blue worms are shorter than European nightcrawlers.
With these tips in mind, you can NEVER miss a blue worm when you see one.
When a blue worm is in a dark or gloomy area, it usually appears to be a blue to blue-purple color.
However, when it comes to the light, it still maintains the blue to blue-purple color but with an iridescent sheen.
When looking for blue worms, you might confuse their color for the African nightcrawlers; the difference is that blue worms are shorter and thinner than them.
Another notable feature of blue worms is their Clitellum (also known as the Saddle).
Their Saddle blends with the rest of their slimy body making it quite difficult to spot.
However, a pro tip is to look out for the lighter part of the worm’s body; there, you’ll find the Clitellum.
We have a separate article if you want to learn about the function of the clitellum in worms.
Commonly in worms, you will find brandings as they make efforts to stretch out and during movement.
The case isn’t the same with blue worms as they do not possess obvious branding when they move around.
Use as bait worm
Because of their thin and erratic wriggling movements, some fisherman feel the blue worms are not exactly cut out for being bait worms.
Though many experienced anglers love them for their shine and movement which make them great bait worms once you learn to hook them effectively
Movement of Indian blue worms
One often used method of identifying blue worms is their rapid movement.
Unlike its friendly neighbor, the red wigglers, blue worms move very fast as though they are in a hurry to catch the bus.
More so, you can catch them flailing around when disturbed like the Alabama jumper, but not with quite the same energy.
To identify whether or not the worm you’re staring at is a blue worm, you should consider the environment you find it.
Blue worms, like the vast majority of worms, prefer to reside in a moist environment.
Moist is okay, however, a wet environment and bedding material is not their preference and may prompt them to escape. (You can refer to the quick fact sheet above to see the kind of environmental conditions they will be comfortable in).
Diet of blue worms
Blue worms will eat scraps of fruits, veggies, cardboard, and newspapers as well as plenty of other organic materials.
Indian Blue Worms Life Cycle
Blue worms reproduce and grow at a rather astonishing rate.
The mature blue worms have been known to deliver approximately 19 cocoons a week if their environment is optimal and from each of them, usually one baby blue worm emerges.
Once hatched, their journey begins. Another reason Indian blues are known to reproduce exponentially is because reaching sexual maturity early is one of their traits.
It takes them 21-35 days to sexually mature.
Their cycle of reproduction is remarkable but of course, many factors influence reproduction rates.
These numbers mentioned are for ideal conditions which includes food sources, temperature, and moisture conditions.
These are just basic guidelines for what they need for an effective reproduction cycle.
Where Do Blue Earthworms Live and Where Are They From?
Since they are known as Indian Blues or Malaysian Blues, you won’t be surprised to learn that they originate from Asia. But they are also commonly used in Australia too.
Blue worms find solace in living in dense tropical areas with temperatures of 70 F to 80 F (21 C – 26 C).
Blue worms are top feeders or surface dwellers (epigeic) and can be found alongside their food source, or right below it.
Simply put, where you find these food sources in great supply, there, you’ll find a heavy presence of blue worms if they’re common in your location.
To recap, blue worms live beside or inside their food sources and they are tropical species from the tropical regions of Asia.
What Do Indian Blue Worms Eat?
Although we’ve given a bit of information and insight above into what blue worms eat, this section goes more in depth about their diet.
Blue worms are vast eaters and the aftermath of their voracious eating leads to effective worm castings (worm poop) and happy worm farmers.
So, if you have a worm farm, or you’re aspiring to enter the business of worm farming for profit, check out the following food they eat and the ones that aren’t a good idea to feed worms and can affect their habitat.
What to Feed Blue Worms
1. Commercial worm food. You have this as worm chow.
2. Vegetable Waste (carrots, lettuce, beans, peas, leaf vegetables).
4. Garden Waste – Bean stalks, pea vines.
5. Tree leaves (avoid exotic leaves)
6. Crushed egg shells
7. Old animal manure (cow manure, horse manure)
8. Shredded cardboard.
9. Fruit waste (avoid citrus fruits).
What Not to Feed Blue Worms
1. Cooking oil or grease
3. Citrus fruit
4. Dairy waste
5. Pet waste
6. Human waste
Though the worms can and often will eat the above foods in small amounts, too much of them can ruin a worm bin environment, invite pests and cause a decrease or mass exodus of your blue earthworm population (who are more than happy to attempt escape as soon as they detect a change to their environment).
Are Blue Worms Good For Composting?
Blue worms are often underestimated when talking about worms to use in a worm bin or worm farm, usually in favor of red worms.
Though they require more maintenance than the reds or nightcrawlers, they have an appetite far more vicious than most worms, as well as a high cocoon production rate (they are FAST breeders) with adults maturing quickly.
They are perfectly capable of producing worm castings quickly and facilitate a fast composting process from your compost pile and organic waste.
Due to the learning curve of keeping Indian Blues happy, we’d recommend starting slow or starting with the easier red worms or nightcrawlers.
Are Blue Worms Rare?
No, they are not.
The blue worms (Perionyx Excavatus) can be found anywhere you find their food sources.
However, there is another species of blue worms that a lot of novices will mistake for our prolific composters.
This blue worm is known as North Queensland’s big blue earthworms [Terriswalkeris terraereginae] and they are scarce to find because they live very deep in the soil.
We are pointing out this fact so that you do not go on a frenzied search looking for the wrong blue worms in the soil.
What Other Names Are Blue Worms Known By?
Blue worms go by other common names and they are; Indian blues or the Malaysian blues.
Key Differences Between Indian Blue Worms and Other Earthworms
There are thought to be almost 10,000 species of worms in the world, but only about 5-7 of them are good for composting and our friend, the Indian blue worm is among them.
So, what makes them so special from other kinds of worms?
In this section, we’ll be taking a quick rundown of the major differences between the Indian blue worms and their close competitor, red wigglers.
1. Temperature Preference
Red wigglers can stay in environments with the temperature up to 55°F-90°F [They can tolerate a wide range of weather conditions]
On the other hand, blue worms do not have such capacity and can only tolerate warm temperatures from around 70 to 80 degrees Fahrenheit.
2. Less Prominent Banding
You’ll find a more distinct yellow and obvious banding pattern from the head of a red wiggler down to its tail where the yellow coloring is more prominent.
Meanwhile, the Indian blue worm, which isn’t totally blue, has a rather iridescent sheen with a similar branding pattern.
However, the Indian blue worm doesn’t have the vibrant yellowish coloring of the red wiggler (apart from on the clitellum!)
In terms of responding to events or elements such as handling and light respectively, the Indian blue worm is quick and sharp to react.
On the other side of the spectrum, red wigglers are more calm and reserved when faced with a situation, moving less erratically.
The mature red wiggler has a bulging clitellum, compared to the Indian blues clitellum which is more flush with its body.
This is one of the more easily identifiable features of Indian blue worms vs red worms.
Those are the key differences to note when separating red wigglers from Indian blue worms.
Which Other Types of Worms Are Blue?
Some other worms are blue and not to be confused with the Indian blue earthworm. They include:
1. HOTHAM’S BLUE WORM: Blue Planarian (a flatworm – learn the difference between flatworms vs earthworms.)
2. North Queensland’s big blue earthworms [Terriswalkeris terraereginae]
Other Uses for Indian Blues
- Feed for pet reptiles, birds and others.
- They make a very good bait worm
Overall : Are Blue Worms Good or Bad?
Blue worms mean different things to different people.
In the Northern part of America, they are often thought to be pest worms and to be gotten rid of at first sight.
However, to advanced vermicomposters in the US and people in other parts of the world, especially in the tropics, Indian blues are highly desirable composting worms.
In Australia, they’re even used as sustainable water treatment, removing heavy metals as part of a natural reed bed system.
Most people find it difficult to differentiate a blue worm from other worms sold in the market or when scrambling the soil in search of them.
You could unwittingly pick up undesired worms for your vermicomposting activity and so many worm farmers complain of Indian blues being mixed in with worms that they buy.
Another scenario is being duped by a dishonest (or usually unknowing) blue worm vendor and being sold red worms instead.
Ultimately, they are fantastic decomposers but they have a tough learning curve.
If you can master them and create an optimal environment for them, they’ll work well for you in return.
This article has extensively talked about the Indian blue worms, their remarkable composting ability (though it comes with a degree of difficulty!), and all other facts you need to know about them.
For Vermicomposting: While some may see them as among the least desirable composting worms, it is more than possible to get a good vermicomposting result with them.
The learning curve is harder than the European Nightcrawlers and red worms but if you can pass this interesting challenge and can handle the large quantities they will inevitably reproduce, then they’re an ideal breed.
Start with a small handful.
Water Sci Technol. 2005;51(10):129-38. Aspects of design, structure, performance and operation of reed beds–eight years’ experience in northeastern New South Wales, Australia. PMID: 16104414 – https://pubmed.ncbi.nlm.nih.gov/16104414/