What Is an Isopod?

If you've never heard of an isopod before, you're not alone. At expos, we often meet people who stop at our table and ask:

“What are those?”

Isopods are small terrestrial crustaceans related to the crabs, shrimp and other crustaceans that live in water. They are commonly known as pill bugs, woodlice, sow bugs, woodlouse and rolly-pollies, depending on where you live.

Unlike their aquatic relatives, terrestrial isopods have adapted to life on land. They can be found living beneath leaves, logs, stones and other damp places in environments all around the world.

And yes — they make fascinating pets.

Why Keep Isopods?

Isopods are becoming increasingly popular as pets and as part of bioactive vivariums and terrariums.

🌱 Terrarium → focused on keeping plants in a habitat.
🦎 Vivarium → focused on keeping animals in a habitat

They are small, fascinating animals that are surprisingly active and social. Once you start watching a colony, you'll quickly discover that there is much more happening in an isopod enclosure than you might expect.

They:

are fascinating to watch as they explore their enclosure;
come in an incredible variety of colours, patterns, shapes and sizes;
are relatively inexpensive to keep;
are quiet and require very little space;
can be remarkably hardy, depending on the species;
reproduce in captivity, allowing a small colony to grow over time;
make excellent inhabitants of many suitable vivariums and terrariums;
and are a great way for children and adults alike to discover the world of invertebrates.

Some species are particularly easy for beginners, while others are more specialised and require greater attention to humidity, ventilation, temperature and feeding.

There is an isopod for almost every level of keeper.

Is an Isopod an Insect?

No! Although they are small and have many legs, isopods are crustaceans, not insects.

They belong to the order Isopoda within the crustacean group. Their relatives include crabs, lobsters, shrimp and other crustaceans [Boyko et al. 2026].

Terrestrial isopods are simply crustaceans that have adapted to living on land.

This is one of the things that makes them so interesting: you're essentially keeping a tiny land-dwelling crustacean.

Isopods in Nature

In nature, terrestrial isopods are an important part of the decomposition process.

They feed primarily on decaying organic material such as dead leaves, rotting wood and other plant matter. Some species will also consume fungi, microorganisms and animal matter when available.

As they feed, isopods help break down organic material into smaller pieces, contributing to the natural recycling of nutrients.

This is why isopods are often called part of the “clean-up crew” in a bioactive enclosure.

They don't magically clean an enclosure by themselves, however. Instead, they work alongside other organisms, microorganisms, fungi and plants to create a functioning miniature ecosystem. Many isopod keepers also recommend springtails as a complement to an isopod enclosure.

Isopods as Pets

One of the most appealing things about keeping isopods is that you don't need a huge enclosure or complicated equipment.

A healthy colony needs the right combination of:

Moisture
Food
Shelter
Leaf litter
Calcium
Airflow

Different species have different requirements, so there is no single setup that is perfect for every isopod.

A tropical Cubaris, for example, may require very different conditions from a hardy Porcellio species.

Understanding the needs of the species you are keeping is therefore one of the most important parts of successful isopod keeping.

What Do Isopods Eat?

Isopods are primarily detritivores [Zimmer 2002]. In nature, much of their diet consists of decomposing plant material.

Leaf litter is one of the most important food sources in an isopod enclosure [Isopods.co.uk 2026].

They also benefit from additional foods, including suitable vegetables, decaying wood and other organic material. Many captive colonies are also offered additional protein and calcium to support growth, moulting and reproduction.

A simple way to remember the basics is:

Leaves to live.
Protein to grow and reproduce.
Calcium to build their exoskeleton.
Moisture to breathe.

Do Isopods Need Water?

They don't drink water in the same way that mammals do, but terrestrial isopods do require moisture.

Isopods are crustaceans and breathe using gills (specialised respiratory structures associated with their pleopods [Tan & Monteiro 2025]).

This is why even species described as “dry” or “arid” still need access to moisture.

The goal is not necessarily to make the entire enclosure wet. In many species, the ideal setup provides a moisture gradient, allowing the isopods to move between wetter and drier areas according to their needs.

Why Are There So Many Different Isopods?

Once you discover the world of isopods, you'll quickly realise that “an isopod” can mean thousands of very different animals.

There are tiny species, large species, fast species, slow species, species that roll tightly into a ball and species that simply run for cover.

There are isopods with:

bright yellow markings;
red and orange colours;
white and black patterns;
metallic-looking bodies;
unusual shapes;
spines and projections;
and an enormous variety of natural and selectively bred colour morphs.

This diversity is one of the reasons isopod keeping has developed into such a fascinating hobby.

Isopods and Bioactive Vivariums

Isopods are particularly popular in bioactive vivariums and terrariums.

In a suitable enclosure, they can contribute to the decomposition of dead leaves, plant material and other organic matter. Their activity becomes part of a miniature ecosystem rather than simply keeping an animal in a box.

They can also be fascinating animals in their own right.

Many keepers eventually discover that they are not simply buying isopods to clean a vivarium — they are keeping the isopods because they enjoy the isopods.

Are Isopods Easy to Keep?

Some are.

Some aren't.

One of the biggest mistakes a new keeper can make is assuming that every isopod species has the same requirements.

Hardy species such as some Porcellio and Armadillidium can be excellent choices for beginners. More specialised species, such as Cubaris, may require careful control of humidity, ventilation, temperature and food.

The good news is that you don't need to start with a complicated setup.

The key is choosing a species that matches your experience and then providing the conditions that species needs.