Red Wigglers Vs Indian Blues: How to Tell the Difference

There are some surprising discoveries new vermicomposters will make as they begin their vermicomposting journeys.

Maybe it’s learning fun facts about worms having 5 hearts.

Maybe it’s discovering that there are over 7000 species of earthworms and that only about 5 to 7 of them are any good at vermicomposting.

 And maybe it’s learning that those red wigglers in their worm bin aren’t even red wigglers at all, but a different species altogether.

This article will explore the similarities and differences between red wigglers and a similar looking composting worm called the Indian blues.

Introduction to Red and Indian Blue Worms

Red wigglers, aka eisenia fetida, are the most common composting worm in the world. Nearly any worm breeder who grows composting worms for sale sells this species, or at least intends to. (More on that later). 

A small worm of the epigeic variety, the red wiggler is hardy and adaptable to a wide range of climactic conditions, and is the worm I recommend most vermicomposters start out with.

Read the Urban Worm Guide to Red Wigglers!

Indian blue worms, aka perionyx excavatus, are another epigeic, surface-feeding worm. “Blues” are similar in size to red wigglers and are also considered to be prolific composters; some say even better than the red wiggler.

Similarities Between Red Wigglers and Indian Blues

At first blush, there’s not much to differentiate between reds and blues.

Composting Ability

As mentioned above, both red wigglers and Indian blues are epigeic, surface-feeding worms who process organic waste above the topsoil and in very loosely-packed material like leaf litter and manure.

Of the nearly 7000 to 9000 earthworm species identified by scientists, these make up two of the seven species generally used in a vermicomposting environment.

Size

There’s not much difference in size between the two species. Both red wigglers and Indian blues will reach a maximum length of 3 to 4 inches.

Thickness is similar too, with the red wiggler being just a little chubbier than a blue.

Why Do We Care?

Both red wigglers and Indian blues are excellent composters. They look similar. They eat the same things.

They’re both small, epigeic composters.

Well the first reason we care is that Indian blues are often – unknowingly or knowingly – sold as red wigglers. On principle, customers should get what they pay for.

But we should also care because one weird and potentially messy behavior that Indian blues exhibit from time to time. 

We get to that below.

Differences Between Red Wigglers and Indian Blues

To the untrained eye, there is no real difference between the two. 

But to the trained eye, there is no way to NOT see the difference as there are some subtle but significant distinctions in terms of appearance, movement, and behavior in certain meteorological conditions.

Less Prominent Banding

Red wigglers have a more distinct yellow banding pattern that terminates on their tail end with a concentrated yellow tip.

Indian blues, which really aren’t blue at all except for maybe an iridescent sheen, have the same banding pattern, but lack the vibrant yellowish coloring of the red wiggler.

Raised vs Flush Clitellum

Probably the easiest visual “tell” of an Indian blue is the lack of a raised clitellum, the fleshy, body-encircling band that everyone associates with earthworms.

On an Indian blue, the clitellum is there, but it is flush with the body, closer to the head and less prominent.

Temperature Preference

One the the biggest selling points of the red wiggler is its tolerance for a wide range of temperatures, generally between 55°F-90°F.

The Indian blue, also known as the Malaysian blue, is a tropical worm and prefers warmer temperatures though I’ve seen blues survive the winters in my Philadelphia-based vermicomposting operation.

Movement

These worms simply move differently.

The Indian blue exhibits more activity than the red wiggler, sometimes thrashing around in response to light or being handled.

The red wiggler is generally more…..chill.

The Indian blue will also become very elongated, seemingly doubling its own length, when moving along a surface.

Tendency to Attempt Escape

THIS is why you care about whether or not you have red wigglers or Indian blues in your worm bin.

Many alarmed worm bin owners report that, all of a sudden, hundreds of worms began escaping what seemed like a happy, healthy worm bin.

Often, this “jailbreak” happens at the same time as an approaching thunderstorm. While we lack the technology to poll the worms as they leave the bin, we can only assume that the drop in barometric pressure that precedes a thunderstorm causes them to freak out, for lack of a better term.

Not all of the worms giddy up and go, but enough of them do that it’s alarming.

The escaping worms are usually….Indian blues.

Visual Comparison of Red Wigglers and Indian Blues

Want to Learn More?

Red Wigglers Vs Indian Blues: How to Tell the Difference

Why Do Growers Sell Blues as Reds?

The short answer is that maintaining species purity is difficult and most customers don’t know or care.

Within the knowledgable, hardcore vermicomposting world, a few large online sellers have a reputation for selling blues as red wigglers.

While it is likely never an intentional act, it may very well be a conscious one. (This distinction may not matter mush to an irritated consumer who learned they have a bin full of blues.)

But as someone who has attempted to do my own worm breeding, I sympathize with these sellers because it is damned hard to ensure species purity in a small operation, let alone a large one.

When considering an online purchase, you can often identify when a worm seller is unable to ensure species purity. Look for product titles like “red worm mix” or read the fine print for disclaimers about species purity.

But remember…..blues might be present in the shipment of worms regardless of what is found on the website.

Summary: Ford Taurus Vs Jaguar

If it’s true that Indian blues are more prolific composting worms, then there’s an analogy that I think is apt.

The red wiggler is like the Ford Taurus. Not the coolest, sexiest thing around, but probably appropriate for the widest range of people. If your kid got to choose their first car, then you’d probably be OK with a Taurus.

The Indian blue is a Jaguar; maybe a better performer but also more likely to cause you heartache. And you – and your insurance company – would not be thrilled with your 16-year-old bringing it home.

But from a purely vermicomposting perspective, both red wigglers and Indian blues are excellent decomposers and will provide you an excellent end product for use in your garden or agricultural endeavors!

Need Some Red Wigglers? Or European Nightcrawlers?

25 thoughts on “Red Wigglers Vs Indian Blues: How to Tell the Difference

  1. Yup, your analogy about the Ford Taurus and the Jaguar is spot on, although I lean toward the Nissan Sentra myself, lol.

    I learned about Blues the hard way two years ago, when a neighbor “gifted” me with her worms before the family moved away. At first, I thought the worms were going nuts because there wasn’t any food in the bin, it was soaking wet and the bedding was cold. However, even with the best bin conditions, I could not count on them staying in their zone. Randomly, I would find dead bodies on the floor near the bin. Very disconcerting, and nothing I did to appease them made a difference.

    They are also smaller overall and MUCH faster. Plus, they could care less about the light. It took me a bit of research to figure out that they truly are a different species, because there hasn’t been a lot of info about them on the Internet until more recently and this was all pre-Pandemic.

    Fortunately, I never combined them with my original herd of red wigglers, whose ancestors were purchased in 2012, before the whole “mixed” thing. I am letting the Blues slowly die out, both from natural attrition and their own suicidal choices. Even with the small number that remains, they STILL go kamikaze and leave the bin. Not cool.

    They might compost their materials a little more quickly ~ it’s hard to tell, most days ~ but for me, it’s not quick enough to make them worth the extra aggravation. Not. At. All.

    “I guess that’s why they call it the Blues… ” Thank you for putting a spotlight on the issue. Hopefully, enough people read this article and pay attention. Otherwise, they’ll be singing along with Elton John, lol. 😀

  2. Wow, I think I might have Indian Blues or a combination. I can’t put a blanket on my worms or let them be in the dark without a huge, mass exodus. I am going to for sure look closely and see. As long as I leave a light on 24/7 I’m OK but without it – well, you get the picture.
    Thank you so much for all the info you provide. And your products are so good. I wish I had been aware of your company when I bought my first worms. When the weather warms and I can put them outside again I will start a 3rd bin and order from you.
    I am also drooling over the Urban worm bin but I am a senior on a fixed income so for now my plastic bins are working.
    Have a great holiday season.

    1. Hey Linda,
      I’m glad I could help and thank you for the kind words! And there’s no need to buy anything from me to be a card carrying member of the “Urban Worm Nation!” 😉
      Cheers,
      Steve

      1. Yes, I know I don’t have to buy anything – you’ve been great about giving me feedback. But come Spring, I’m thinking I can put my blue worms in my outdoor compost and get some red wrigglers and then in the winter when I bring them in perhaps I won’t have to work so hard to avoid having worms crawling out of my bin.
        After looking at your pictures the worms I have definitely look like blues and I’d complain to the company but I’ve worked out a way to keep them in and they are producing beautiful castings so for now I will just maintain and enjoy what I have.
        Thanks again for all the info. It is wonderful to have someone who really cares about their customer’s success.

    1. Hi Mariano,
      If at all possible, it’s best to let them be. Otherwise, the only thing to do is manually inspect and remove. unfortunately. The Blues prefer warmer environments than reds, but they seem to be hardy enough to survive no matter what.
      Steve

    2. Rather than remove the blues, start a fresh well isolated bin for hand selected reds. Go through and hand pick out reds one by one until you have maybe 50 clean worms that you are 100% sure are all reds. Don’t transfer any bedding material as it may contain blue eggs or tiny juveniles. Best to do this in small batches of maybe 10 each so that you can more easily give them a second check before adding to the new bin.

      After the new isolated bin has become well populated you can dispose of the old bin and be sure to clean it and the area thoroughly to avoid stowaways of all life stages. This is the only practical way to have a known population free of blues. This type of species isolation is used in many biological labs and operations, with some requiring multiple clean transfers on a schedule where the contaminating species is more closely mixed. These worms are comparatively pretty easy to isolate and so should only take one round if done with care, though you could do a fresh isolation every year or two just as a preventative measure in a larger operation keeping breed stock separate and upstream of any general compost production.

  3. Perfect timing! Hope you solved my mystery. I found tons of dead worms several weeks ago right outside one of my worm bins and was so upset. I thought it was that maybe it was because the soil was not wet enough or they were getting too cold. I dampened soil and again it happened. I then bought the large coir matt from you and cut it it to fit the bin I was growing these guys in. I also added additional shredded newspaper to the top. Seems to have helped but think I found more after that too…. None have escaped from the Urban Worm Farm. The ones that escaped were from was a large rectangular tote that I am using to supplement the Urban Worm Farm.

    So glad to hear that it might not be what I was doing, I felt terrible. I will check and see if I can identify any Indian blues in that bin. Wonder how that would have happened since both bins originated from same original worms. (I started my whole worm composting with just 5-6 worms that were given to me about 3.5 years ago.)
    BTW, really love the Urban Worm Farm/Composter.

  4. Thanks Steve. You solved a huge mystery for me. Seven of my 12 herds are from a local farmer’s compost pile and I thought they didn’t have pronounced clitellums because I was not feeding them correctly or taking care of them properly. But I also suspected they were a different kind of worm and was trying to figure out how to identify them. You solved a huge riddle for me so I have created a bit of a video to show people some close up views and microscope shots of my Indian Blues: https://youtu.be/DCINGBgV7is

  5. Hi Steve,
    Thanks for the explanation. Here in Cleveland we probably need the more cold hardy red wigglers. I took a look at the link to the Red Wigglers sales page you posted below your article and it actually also has a disclaimer “May contain some blues.”

  6. Hi Steve.
    Might sound like a stupid question but is it possible for worms to cross breed being over 7000 types of worms it seems like more of a probability than not.

    Cheers

    Bob Taylor
    Australia

    1. Not a stupid question! As a general rule, worms cannot interbreed. However, there is evidence that the red wiggler (eisenia fetida) and tiger worm (Eisenia andrei) are able to interbreed.
      Cheers,
      Steve

  7. Yes I’m starting out with a box made out of one sheet ply wood .14 inches by 15 inches buy 19 inches by 46 inches long .That way I can have a lid with a pitch roof .I’m seeing up to feed chickens worms so I plan to have escape holed on the ends of my boxes But I’m in alpine California that can get into the low 30s and up into the 110s degrees so I’m thinking to decide the box with one side for red and one side the blue worms .Can I buy them from you ? Thank Kelly

  8. Steve,
    Thanks for all the info. I saw you on Epic Gardening. I am trying to start composting. I am thinking of doing a combination of bokashi and a worm farm. I wish I could afford a fancy pre made set up but Covid has left us unemployed for going on over a year. Since we are on a budget, growing some of our produce and herbs with homemade compost made from our food scraps seems like a great idea (while limiting waste that is going to the landfill). We live on the Texas Gulf Coast and need worms that can stand the heat. Where can I buy Blues? Any tips on keeping them from wiggin’ out with our always rainy weather would also be much appreciated.

    1. Hey Misty! Thanks for checking in. I’m not sure of anywhere that sells purely blues. And I *really* don’t know how to keep them from wigging out. 🙂

  9. Very interesting; I too have bought in worms, tried to treat them well, only to have them disappear. Maybe this is why. I may have to re- populate my bins and will certainly look at being a bit more proactive in checking which species I am using. However, I live in tropical north Australia so have you any recommendations regarding species, assuming that any worms I buy in will be a mixture? Also how to distinguish other composting worm species? Maybe I can start my own experiment with a few bins with different species and see which work best up here!

    1. You may find that African nightcrawlers do well in your tropical environment. They do best with higher temps. They are a bit larger and easily distinguishable.

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