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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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.

The term for such a thing is a bioactive 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.

Leaf litter bugs do this naturally in the wild, and they can do it in your terrarium, too.

Here are the best bugs for terrariums.

Springtails for Terrariums (Collembola sp)

Springtails are the perfect compromise for someone who wants the mold-fighting, terrarium-cleaning dream team without giant bugs crawling all over the place.

These tiny critters are only 1/16″ at full size, and they’re really more jumpers than they are crawlers (hence the name). So it’s always best to use them in a closed terrarium.

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.

👉 In my Essential Guide to Tropical Terrariums, I recommend springtails for terrariums across the board.

Springtail Cultures

Springtails are typically cultured amongst chunks of charcoal. Mostly because the porosity of charcoal lends itself to being a breeding ground for bacteria and fungi, which the springtails can feed on.

It’s also a nice, easy (non-messy) way to keep and/or transfer them.

Or, substrate works well, too. Then you can just mix it right in without any extra fuss.

How many springtails do you need?

The amount of springtails you’ll need depends on the size of your terrarium, but even just a small colony can be hugely beneficial.

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Different varieties can be found to best match your terrarium conditions (or color preferences). Though people report that temperate springtails tend to adapt to tropical terrarium conditions just fine, too so I don’t think it matters too much which you get.

I discuss the differences (or lack thereof) in my guide to Temperate vs Tropical Springtails.

Isopods for Terrariums

Isopods go by many names, but you may know them as pill bugs, rolly pollies, or just good old-fashioned woodlice here in the UK.

They’re often much larger than springtails, so I guess they’re more for the bug enthusiasts out there. But some species like the Dwarf White Isopods are not that much bigger than springtails.

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.

One important thing to note with isopods is that they need high humidity to survive. They don’t have lungs per-se, and they instead breathe through gill-like structures beneath their armored carapaces.

So, humid terrariums are a perfect fit!

👉 For more isopod inspiration, see 12+ Funky Types of Isopods to Collect.

Isopod Cultures

When it comes to isopods, there’s a huge diversity in shape, size, and colors.

So there really is something for everyone! However, their environmental needs 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’re going to want an isopod culture that thrives in the warm temperatures and high humidities of a tropical terrarium.

Dwarf White Isopods make an amazing cleanup crew for small and large terrariums alike.

They’re adaptable, efficient, and they breed like crazy!

Or, the larger varieties (e.g., Zebra Isopods and Dairy Cow Isopods) make great clean-up crews for larger terrariums and vivariums too.

👉 Check out my Isopods for Sale guide for more help, or shoot straight over to Rubber Ducky Isopods to see their range.

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

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? 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 potentially some value in adding some terrarium worms, but they’re very rare use cases.

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.

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.

Finding appropriate springtail and isopod cultures online is increasingly easy these days. Many online companies stock a variety of microfauna for the terrarium and herpetoculture communities.

That said, we’ve partnered with Rubber Ducky Isopods for their huge range, high-quality products, and (super refreshing) transparency.

Shipping is always included in the price – so you know exactly what you’re paying upfront – and they really go out of their way to ensure your order arrives safe and healthy.

• For springtails, check out their Springtails Master Culture.

• For isopods, check out their complete range here.

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.

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.

Finally, we move from pets on 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.

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.

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 (or if you want to get really fancy, why not check out the actual Rubber Ducky Isopods?).