The Best (& Worst) Terrarium Insects and Bugs: 12+ Species

Today, we’re talking about terrarium bugs. The good, the bad, and the ugly.

Love them or hate them, insects and bugs can make a valuable addition to a terrarium ecosystem.

Of course, that’s provided you get the right ones.

Some can help keep your terrarium clean, rich in nutrients, and free of pests. Whereas others simply are the pests…

In this article, we’re going to identify which terrarium insects and bugs are friendly (and which are not) and where to find some really cool varieties.

Ready to unearth some gems? Let’s go.

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Bioactive Terrarium Bugs and Insects

First up, we’re starting with the good guys.

Bioactive terrarium bugs are a fantastic addition to any terrarium setup.

After all, being able to decompose organic matter – and process it to become available nutrients for your live plants – is part of being a truly self-sustaining terrarium.

What makes this possible is the microorganisms (bacteria and fungi) and the microfauna (insects and bugs) that are able to help the decomposition process along. The term for such a thing is a bioactive terrarium.

Here are the best bugs for terrariums. 👇

1. Springtails in Terrariums

Springtails are the single most effective bioactive terrarium bug.

Conveniently, they’re also the easiest to get started with.

Requiring almost no care at all, they’re the perfect compromise for someone who wants the mold-fighting, terrarium-cleaning dream team (without the additional needs of a pet).

These tiny critters are only 1/16″ at full size, and they’re really more jumpers than they are crawlers (hence the name).

It’s always best to use them in an enclosed terrarium, but more to meet their moisture requirements than stop them escaping. We’ve never had issues with that.

springtails in terrariums
They can climb dirty glass a little, but they’re honestly just feeding here.

Springtails are detritivores, which means they love to feed on dead organic plant matter, but their favorite food is fungi. So, in the absence of any mushrooms in your terrarium, they’re going to feed on the most abundant source – mold.

That’s right, you can say goodbye to those awful mold blooms with a colony of springtails!

Different varieties can be found to best match your terrarium conditions (or color preferences). But temperate springtails do fantastically well in tropical terrarium conditions, too – so it’s not make or break.

We sell the most tried-and-tested species in the industry – Folsomia candida, otherwise known as Temperate White Springtails.

terrarium springtails
👉 Grab a springtails colony today.

The amount of springtails you’ll need depends on the size of your terrarium, but even just a small colony can be hugely beneficial. Honestly, they tend to reproduce very quickly, so you don’t need to always start with a giant culture.

A few springtails and a little bit of patience go a long way!

2. Isopods in Terrariums

Just like springtails, isopods will readily feed on decaying organic matter and help keep your terrarium clean and fertile (in fact, springtails and isopods make a great team).

Easily the best thing about isopods is their huge diversity in shape, size, and colors.

However, their environmental needs can differ quite a lot, too, so it’s important to get the right species for your setup.

Tropical species are a good starting point, as you’ll want an isopod culture that thrives in a closed terrarium’s warm temperatures and high humidity.

isopods in terrarium
We’ve got Dairy Cow Isopods and Dwarf White Isopods working together here.

There is a wide variety of terrarium-suitable species, those are just a select few bioactive choices.

If you prefer to have a cool isopod pet in your terrarium (and don’t expect/need it to do much cleanup work) then you’ve even more funky isopod species to choose from.

👉 Check out our full collection of Isopods for Sale on the store!

Next up, we have the bioactive bugs with very niche use cases.

3. Worms in Terrariums

Worms are fantastic at aerating the soil and reaching areas that other bioactive bugs won’t.

So, should you put worms in a terrarium? In most cases, probably not.

  • Despite always being beneath the soil, they can make a real mess on the glass.
  • Different worm species require different levels of depth and space, which are difficult to achieve in a terrarium.
  • They’re a little too effective at consuming organic material. They’ll often chew through your substrate itself, turning into a thick mush.

For larger projects, there’s value in adding some terrarium worms. But I wouldn’t bother for your average terrarium; I don’t think the benefits outweigh the negatives.

4. How About Millipedes?

Much like pill bugs, millipedes are effective decay-munching machines… that unfortunately, also run the risk of feeding on your plants.

Being larger (and a touch more challenging to keep) than isopods, they don’t see nearly as much use in terrariums and vivariums.

That said, millipedes do make for cool pets, and they are solid bioactive cleaners.

bumblebee millipede
Here’s one of my baby bumblebee millipedes.

I’ve seen them used in larger setups, and you can supplement their diets with apple slices and such. So, hopefully, if there’s no lack of food, then they wouldn’t turn to your plants!

Check out my terrarium millipede guide for the full rundown.

Closed Terrarium Bugs and Insects as Pets

Snails, Slugs, and Beetles

The likes of snails, slugs, and beetles will all love being in a terrarium.

Small, easy to keep, and full of diversity, why not go for it?

Well, just bear in mind that all of the above are inclined to eat plants from time to time. Much like the millipedes, if you’re feeding them with supplementary food, then they may leave your plants alone. 

Plant choice is critical here, too, as there are plants out there that snails tend to avoid. Check out my Snail Terrarium Guide for my top plant picks.

In fact, roaches might be a better choice if you want to be extra careful.

Mantis and Ladybugs

One way to avoid collateral plant damage is to pick carnivorous bugs!

Naturally, this completely changes the game in terms of how you care for them. 

Praying mantes are a common (and super cool) choice that can work well in an insect terrarium.

praying mantis on a tree
We actually found this little guy on a walk in Seoul, Korea!

Ladybugs, however, are voracious aphid-eating machines and will quickly run out of available food. I wouldn’t be surprised if a ladybug devoured a springtail population given the chance.

Just note that any carnivorous insects might well eat your beneficial terrarium bugs. So popping them in with your usual cleanup crew is probably a bad idea…

Spiders and Scorpions

Okay, so I know spiders and scorpions aren’t insects or bugs, but they definitely fall into the same line of questioning as the rest of the critters on this list. 

These burrowing pets can both thrive in a targeted terrarium environment. But that’s definitely way out of my expertise (and comfort zone).

Check out my terrarium pets guide and insect and bug pets guides for more help.

Terrarium Pests

Finally, we move from pets to terrarium pests.

Spotted any tiny unidentified flying bugs in your terrarium?

They’re probably one of the bad bugs, I’m afraid. Gnats, mites, and mealybugs are all known plant parasites that can hitch a ride into terrariums via plants and substrate.

These have different negative effects on plants, ranging from generally harmless (just unsightly and annoying) to vitality-sapping swarms.

gnats in terrarium
This here is a fungus gnat, and I absolutely despise them.

Plus, though completely airtight terrariums are immune to external invaders, ventilated setups are not.

I’d be particularly wary of overfeeding any of your other beneficial bugs (especially with wet foods like fruit) as these can attract pests. Little and often is best!

Unfortunately, getting rid of bugs in terrariums can be a challenging task and often involves significant interventions, from quarantining plants to swapping out substrates. 

Sometimes, even just starting over.

So, Does a Terrarium Need Bugs?

The answer is no, they’re not a strict necessity, and I’ve happily grown many a terrarium with bugs and without them.

That said, these beneficial terrarium insects really can make the whole care process much easier.

I’d absolutely recommend at least a handful of springtails in every setup, and isopods bring a lot to the table too.

24 thoughts on “The Best (& Worst) Terrarium Insects and Bugs: 12+ Species”

  1. Nice read as for pinks being unnatural looking they actually don’t appear pink when they eat most foods truthfully I have them and other than being a little larger than the white springtails they’re pretty much the same. I have at least 5 species of springtails living in one of my terrariums. Also certain soil millipede species don’t care for plants at all but likely do feed on plant roots but I’ve never had an issue with them find them beneficial. Also I have a small species of centipede that live in the soil they seem to keep the springtails in check along with hypoaspis miles aka predator mites I also keep in my substrate. I can’t seem to keep isopods in the water dragons terrarium except dwarfs as louse spiders always make their way in somehow. I have used a few beneficial predators to feed on different pests I’ve had over time as removing soils and stuff is simply not an option. One other pest I have though hasn’t been an issue yet but I fear will be eventually is sugar ants they have made their way in there.

  2. I have a closed plant terrarium jar 10” high and 8” in diameter. I have added springtails. Do I have to open the terrarium ever so often to give the springtails air to breathe? If so, how often? Thank you.

    1. Hi Sandra, that’s a good question! I have no idea how much oxygen they need to breathe vs how much is produced in a typical terrarium. That being said, I tend to only really open my terrariums when I’m watering them and my springtails have been absolutely fine. So, I suspect that any typical terrarium care should be enough and you probably don’t have to worry about opening them specifically for oxygenating it.

      1. My tiny first Vivarium is a 5inch by 3 1/4 inch pickle jar. It has 3 woodlice, a fern, and some liverwort. The lid has been tightly sealed for 8 months. The oxygen producing plants must be in ballance with the carbon dioxide producing woodlice.

        1. That’s interesting to hear that even the larger woodlice can be sustained (vs tiny springtails). Good to know! Thanks Tom.

    2. You don’t really need to open the jar. The plants in the terrarium will support the creatures inside by providing them oxygen. Springtails digest the decaying matter and fungi and poop out an amazing fertilizer. But if you want, you can open it for 15-30 mins a week, to get in some fresh air (not really needed). Springtails control their population according to the availability of food inside the terrarium. There is no need to feed them.
      I hope it helped 😁😎

  3. I’m a plant person not a bug person, so I hadn’t put any insects—beneficial or otherwise—into my terrarium (at least not intentionally). I did see some springtails in the soil of a small plant that I put in, though I seem to have springtails in most of my planters and they’ve never been an issue. However… recently I had a little mushroom pop up, which led to two more, which led to spores everywhere and my entire terrarium being coated in white. As I considered what I should do, the population of springtails EXPLODED. They were crawling everywhere, though they did clean up the spores so I can see my plants again. I can see seven more tiny mushrooms popping up and I know it’s only a matter of time before white dust—and the springtail population—takes over everything. How worried should I be?

    1. Hi Eve, I find the springtail populations tend be self-limiting. Once the colony has boomed and consumed all the mushrooms I imagine it’ll die out somewhat. I wouldn’t worry, neither mushrooms nor springtails should be a threat to your plants.

  4. Terrarium newbie here and loving your site – so helpful & informative! My terrarium is about 3 weeks old and I just noticed some mold/fluff growing on my driftwood & one plant. Glad to learn this is pretty normal so now I’m looking into getting some springtails. My only concern is whether they stay in the terrarium or do I have to worry about them venturing out into my house? My terrarium is a 30 gal aquarium. Thanks for any info & keep up the great work!

    1. Hey Debbie, I’m glad you’re enjoying the site! Springtails can escape, and they can jump too (though not that high). I’d still recommend closing your terrarium for the most part.

  5. Hey Dan, my terrarium is about a month old and I was trying to find some springtails in my backyard and I’m worried that I got the wrong bugs and put them in my terrarium. Are there any lookalikes that I should be concerned about?

    1. Not that I’m aware of. Their springy jumps are pretty characteristic though, if they’re hopping around I’m sure you have springtails.

  6. I have a small enclosed terrarium with springtails that came in substrata in a plastic container & feed them on brewers yeast. About 5 weeks after set up now have really small centipedes in the terrarium, they are not in the springtails container & assume the came in the special plants added at set up time. Are they a good or bad thing & do they eat the springtails & or plants.

    1. Centipedes are carnivores I believe, so at the very least they won’t bring any benefits. They won’t eat your plants, but they may eat any other benefitical insects.

      1. Thanks a lot Dan 🙂 for such useful information. Its really awesome to read information on terrariums here which helps all of us over the world!!!

  7. Hi Dan.
    Absolutely lovely read.
    I came across your article because
    only today one of the plants in my mini terrarium has turned to black mush and I’ve noticed some white crawlies on it.
    I was panicking ready to throw the entire thing away but I might not now. Instead, ladybugs seem like a thing I could try (I am a scardy cat).
    I’m still not sure what’s in there or what these bugs are but will try to remove the old plant tomorrow and have faith.

    Thanks 🙂

    1. Honestly I am here for the same exact reason. I noticed about a dozen very tiny white nematodes crawling on the glass and I was wondering whether they’re harmful of not. And if they are, what predator could clean them up?
      Thanks a bunch!

  8. Hi. I am looking into building a terrarium but am really concerned about escaping springtails and about putting in springtails although I understand the need. I also was thinking of using a jar that doesn’t have a lid and trying to find something to fit it Do you have recommendations for lids that springtails can’t escape? PIexi glass, cork, glass with no seal, serán wrap, other?

    1. Hi Katie! As long as a lid doesn’t have holes in you shouldn’t have any issues with escapees (at least we haven’t). We personally use plexi glass or saran wrap and haven’t had any issues.

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