What do isopods eat? A complete isopod food and feeding guide

If you only want the quick answer from this article, this is roughly how I think about the different foods in my cultures:

Essential: Leaf litter and a permanent calcium source.

Core food: Rotten hardwood and a nutritious, organic substrate.

Very useful: Protein, particularly for growing and breeding colonies.

Useful variety: Vegetables and occasional fruit.

Highly recommended: Lichen, with some of my species showing a particularly strong appetite for it.

Optional but very interesting: Fermented or microbially conditioned leaf litter.

My own staple supplement: Organic seven-mushroom powder mixed with spirulina.

Extras worth experimenting with: Nutritional yeast, bee pollen and other simple, concentrated foods.

Please note that this is a general guide. Of course, different species will naturally favour different foods. A large colony of protein-hungry Porcellio will require a different diet and amount of food compared to a few Cubaris or Ardentiella, so I always adjust feeding according to what the colony actually requires and favours.

As I am sure you are aware, leaf litter is an absolute must for isopods - so bear with me, this section is fairly lengthy!

Fallen leaves are a major part of the natural detritus layer that terrestrial isopods feed through. As the leaves age, fungi and bacteria colonise them, tougher plant material starts to break down and the leaf becomes easier to graze. Studies of terrestrial isopods consistently show that the type and stage of decomposition of leaf litter can strongly affect how readily it is eaten.

I therefore use dead, naturally aged leaves, never fresh green foliage as the main litter. I also favour variety. Different leaves vary in thickness, toughness, tannins, nutrients and how quickly they decompose. Some disappear rapidly, while others can provide structure and grazing surfaces for months.

Being based in the UK, I use plenty of European broadleaf litter. Good options I am comfortable using or recommending include the following European and temperate leaf litter:

• Pedunculate oak — Quercus robur
• Sessile oak — Quercus petraea
• Downy oak — Quercus pubescens
• Hungarian oak — Quercus frainetto
• Holm oak — Quercus ilex
• European beech — Fagus sylvatica
• Hornbeam — Carpinus betulus
• Hazel — Corylus avellana
• Silver birch — Betula pendula
• Downy birch — Betula pubescens
• Sycamore — Acer pseudoplatanus
• Field maple — Acer campestre
• Norway maple — Acer platanoides
• Common ash — Fraxinus excelsior
• Small-leaved lime / linden — Tilia cordata
• Large-leaved lime — Tilia platyphyllos
• Common alder — Alnus glutinosa
• Aspen — Populus tremula

Oak and beech are probably the names most keepers hear first, but they don't need to be the entire diet. In fact, experimental work has shown that isopods can sometimes prefer more nutrient-rich litter such as ash and maple over tougher oak and beech.

I also increasingly use Asian and tropical leaf litter, which I particularly enjoy adding to cultures of species originating from Southeast Asia.

Some of the Asian and tropical leaf litter I recommend:

• Purple orchid tree — Bauhinia purpurea
• Macaranga species, including Macaranga pruinosa, M. gigantea and M. peltata
• Indian almond / catappa — Terminalia catappa
• Jackfruit — Artocarpus heterophyllus
• Breadfruit — Artocarpus altilis
• Guava — Psidium guajava
• White mulberry — Morus alba
• Bamboo — particularly Bambusa and Dendrocalamus species

One blend I like to use contains Bauhinia purpurea and Macaranga leaves. I like the contrast because the thinner Macaranga leaves soften comparatively quickly, while the thicker Bauhinia leaves provide longer-lasting cover and grazing material. These sorts of mixtures give the enclosure several stages of decomposition at the same time.

That does not mean an Asian isopod needs Asian leaves. Research has shown terrestrial isopods readily eating introduced leaf species, sometimes as readily as native litter. With that said, I think mimicking their natural environment as much as possible is always a bonus.

I crush some leaf litter through my substrate and leave plenty whole across the surface. I never wait until the enclosure is completely bare before topping it up.

Leaf litter should always be available.

It also provides hiding places, especially for mancae, and creates countless tiny humid spaces between overlapping leaves.

For more on how I incorporate leaves into the enclosure itself, see my isopod substrate guide.

A final word of caution: the lists above are broad, but they are not permission to assume every tree leaf is suitable. I avoid unknown leaves, chemically treated garden waste, roadside collections and anything exposed to pesticides or herbicides. I also don't routinely use resinous conifer needles or strongly aromatic leaves. If I can't confidently identify it, I don't put it in the culture.

On the topic of leaf litter, this is not an absolute but is certainly an interesting feeding idea with some promising published results behind it. Within the hobby it is often called fermented leaf litter, although microbially conditioned or pre-conditioned leaf litter probably describes what we are trying to achieve more accurately.

The idea is simple. Instead of putting completely dry leaves straight into the enclosure, you allow bacteria and fungi to begin colonising and breaking them down first. In effect, you give decomposition a head start.

A 2024 analysis combined 456 measurements from 56 studies looking at leaf consumption, assimilation and growth in isopods and millipedes. Microbial conditioning was one of the strongest factors affecting consumption: conditioned leaves were consistently eaten more readily than freshly senesced litter. That makes biological sense. Fungi and bacteria begin breaking down tougher plant compounds, soften the leaf, and provide another potential food source themselves.

So, how do you make fermented leaf litter?

Start with safe, correctly identified, pesticide-free dead leaves. Moisten them thoroughly without leaving them submerged in stagnant water, then place them in a clean container where they can remain damp with some air exchange. Allow microbial growth and decomposition to begin, checking regularly for softening, earthy-smelling leaf litter. Healthy conditioning and uncontrolled anaerobic rot are not the same thing. If a batch becomes slimy, turns into black mush or develops a strong, unpleasant smell, I would discard it rather than attempt to rescue it.

I recommend introducing conditioned leaves alongside ordinary leaf litter rather than replacing the entire layer immediately. Different species may respond differently, and part of the fun is discovering which cultures consume them fastest. Fermenting leaves is not essential for healthy isopods, and ordinary aged leaf litter works perfectly well. However, as a way of providing softer, microbe-rich food, I think conditioned leaves are genuinely worth experimenting with.

The important word here is rotten. Fresh wood is not the same as hardwood that fungi and microorganisms have spent months or years breaking down. White-rotted hardwood is particularly desirable, having been decomposed by fungi that break down lignin and other structural components of the wood. Good rotten wood is often pale white or cream, soft, spongy or fibrous, and sufficiently decomposed to pull apart or crumble between your fingers.

You can find suitable wood in deciduous woodlands, particularly in fallen branches, old logs and decaying stumps of trees such as oak, beech and birch. Look beneath the bark or inside logs that have been lying on the damp forest floor for some time. The best pieces are often already partially broken down, with a soft, lightweight texture and an earthy smell. Only collect from confidently identified, untreated hardwood, avoiding conifers, contaminated areas and wood showing signs of chemical treatment. Always collect responsibly and obtain permission where required.

I mix fine pieces through the substrate and also provide larger pieces on the surface.

Decaying wood provides a long-lasting source of organic material and another surface full of fungal and microbial growth. This is especially useful for species that naturally spend much of their time buried within decaying forest-floor material rather than sitting on top waiting for supplemental food.

Like leaf litter, rotten wood also reinforces one of the most important ideas in isopod feeding: the enclosure itself is part of the diet. A mature substrate contains humus, leaf fragments, decomposing wood, fungi, bacteria and other organic material. Isopods are constantly grazing rather than waiting for us to deliver dinner.

This is why I put so much emphasis on building a nutritious substrate from the beginning. My isopod substrate guide covers the mixture I use in much more detail.

Yes. Isopods need calcium to build and harden their mineralised exoskeleton, so I keep a calcium source permanently available.

When they moult, they need to mineralise and harden a completely new outer layer. Their biology is quite clever. Before moulting, terrestrial isopods can remove calcium carbonate from parts of their existing cuticle, temporarily store it, then reuse some of that calcium after the moult.

However, this recycling process doesn't recover all their calcium, so they must replenish their stores through their diet and environment. This is why I always provide a permanent calcium source.

This is also why you might notice an isopod eating its own shed exoskeleton. By consuming the discarded cuticle, isopods can recover additional calcium and other nutrients that would otherwise be lost.

Options include:

• Cuttlebone
• Calcium carbonate powder
• Crushed eggshell
• Limestone
• Calcium-rich substrate ingredients

I tend to use more than one source. Calcium carbonate can be mixed through the substrate while cuttlebone or limestone remains available on the surface.

Yes, most isopods benefit from supplemental protein, particularly growing and breeding colonies, although the amount varies greatly between species.

Protein can produce some of the most dramatic feeding responses I see across my isopod colonies.

Large Porcellio in particular can make a piece of dried shrimp disappear remarkably quickly, but plenty of Cubaris, Armadillidium, Troglodillo, Ardentiella and other groups will also take to protein keenly.

Foods I recommend include:

• Dried shrimp
• Quality fish flakes
• Fish or shrimp-based pellets
• Dried mealworms or other simple dried invertebrate foods

Protein provides concentrated amino acids that are less abundant in dry leaf litter. It is particularly useful for rapidly growing and breeding colonies.

There is also experimental evidence that changing dietary protein can alter reproduction in terrestrial isopods, including the number and size of offspring produced. That doesn't mean that more protein is always better - it shows that nutrient balance matters.

I therefore feed according to the colony rather than using one fixed timetable. If the protein disappears almost immediately every time I offer it, I can increase the amount. If it sits untouched for three days, I fed too much.

Two hundred hungry Porcellio and eight slow-growing rare Cubaris clearly shouldn't receive the same portion.

Yes. Fish flakes and shrimp-based fish foods are some of the easiest protein supplements for isopods. I use good-quality fish foods alongside dried shrimp and other simple protein sources. Many commercial fish foods also contain colour-enhancing ingredients, such as astaxanthin and other carotenoids, which can contribute to pigmentation in some animals. I find these particularly interesting for brightly coloured isopods such as Cubaris sp. ‘Lemon Blue’, Cubaris sp. ‘Jupiter’ and Cubaris sp. ‘Cherry Blossom’, where maintaining their striking colouration is especially desirable. However, the extent to which these ingredients directly enhance isopod colouration has not been well established. Fish foods should supplement leaf litter and rotten wood rather than replace them, and I only offer as much as the colony will consume before it begins to spoil.

Yes. Isopods can eat many vegetables and fruits, but I treat fresh produce as an occasional supplement rather than a staple food.

I personally feed protein much more frequently, with vegetables and fruit offered occasionally for variety. In my opinion there is no need to regularly offer fresh produce.

Some of the vegetables I recommend include:

• Carrot
• Sweet potato
• Squash
• Pumpkin
• Courgette
• Cucumber
• Peas
• Green beans
• Broccoli stems and leaves

Carrot and squash are particularly convenient because they don't collapse into wet mush as quickly as some softer vegetables. Cucumber and courgette contain far more water, which can make them useful occasionally but also means they spoil more quickly.

Fruit can be eaten too. Small pieces of apple, pear, melon, banana or berries can provide variety, but I use sugary fruit more sparingly because it breaks down quickly and can attract annoying flies and mites.

Lichen is one of my favourite things to offer.

Lichen isn't simply a plant. It is a partnership built around a fungus living with an alga or cyanobacterium, creating a naturally complex grazing surface. Most of my isopods eat lichen, and some absolutely demolish it. This is especially obvious with my Ardentiella, which can strip lichen-covered wood almost completely clean. For this genus, I personally consider lichen close to a staple. Many Cubaris, Porcellio, Armadillidium and other groups also graze on it, although preferences vary between species.

Unlike a slice of cucumber, lichen can remain in the enclosure for extended periods, providing food, structure and cover simultaneously. I have written a separate guide on lichen for isopods, covering what it is, why I use it, the different forms available and how to collect it safely.

This is probably the most niche part of my isopod feeding routine. I make my own dry powdered feed by combining organic seven-mushroom powder with organic spirulina powder, and it has become a regular staple food across my whole collection.

My mushroom blend contains seven organic mushrooms: Reishi, Cordyceps, Lion's Mane, White Fungus, Maitake, Shiitake and Chaga, which I mix with spirulina.

Fungi already sit naturally within the detritivore food web. Isopods consume fungal material directly and encounter fungi throughout the leaves, wood and substrate they feed on. Mushroom powder provides a concentrated fungal ingredient containing protein, minerals and fungal polysaccharides.

Spirulina provides something quite different. Although commonly called an alga, it is actually a cyanobacterium and, when dried, is extremely nutrient-dense. Its dry matter can contain roughly 50–70% protein, alongside amino acids, minerals and pigments. Together, these ingredients create a concentrated blend of fungal and microbial food with a strong protein component.

I haven't found a controlled study demonstrating that this particular mushroom-and-spirulina blend improves isopod lifespan, growth or breeding, so I wouldn't claim that it does. What I can say is that I use it regularly, my colonies consume it readily, and the response has been good enough across my collection that it has become one of my staple supplemental feeds. I offer a light dusting rather than pouring it into the enclosure, as powdered foods have a large surface area and a little goes a long way in a humid culture.

Once the core diet is right, there is plenty of room to experiment with an isopod's diet.

One food that comes up repeatedly among experienced keepers is nutritional yeast. It is dry, concentrated and easy to sprinkle in tiny amounts. Many keepers use it for both isopods and springtails.

Bee pollen is another interesting option. It contains protein, lipids, carbohydrates and micronutrients, and small granules are easy to scatter across a culture.

Commercial detritivore gel foods can also be useful, particularly when you want something concentrated that can be portioned neatly. Some keepers go further and mix powdered foods such as spirulina or ground shrimp into a gel, allow it to set, then cut it into tiny pieces.

Another niche food is bat guano, although this is one I approach with considerably more caution. Guano is an important nutrient source in cave ecosystems, supporting communities of microorganisms and detritivorous invertebrates, including some cave-associated isopods. Rich in nitrogen, phosphorus and other nutrients, it can provide an additional source of organic nutrition, particularly for species associated with guano-rich habitats. However, excessive guano can deplete oxygen and contribute to harmful waste accumulation. If you are going to provide this, less is more!

Mancae do not need a separate baby diet. What they need is food everywhere. 

This is another reason I put so much emphasis on a great substrate and leaf litter mix. Tiny mancae can remain hidden beneath leaves or within the upper substrate while finding decomposing organic matter all around them. Fine particles of rotten wood and crushed leaves are particularly accessible.

As already discussed, calcium should remain permanently available as the mancae grow and moult.

If you want to understand what happens before those babies appear, my guide to isopod reproduction covers mating, the marsupium and manca development in much more detail.

 I divide foods into two categories: those that should always be available, including leaf litter, rotten wood, nutritious substrate and calcium, and supplementary foods such as protein, vegetables, fruit, lichen and my mushroom-and-spirulina blend, which I provide according to the colony's appetite.

Personally, I feed my colonies every 4–6 days, typically offering protein alongside my mushroom-and-spirulina blend.

If food consistently disappears overnight, consider increasing the portion slightly. If it repeatedly sits untouched until it spoils and goes mouldy, offer less. Rather than a rigid amount, the colony itself is one of your best feeding guides!

The biggest risks usually come from contamination and excess.

I avoid:

• Leaves or plants exposed to pesticides and herbicides
• Roadside leaf litter exposed to pollution and runoff
• Unknown plants that I cannot identify
• Heavily salted foods
• Seasoned or oily human food
• Highly processed foods with unnecessary additives
• Huge amounts of sugary fruit
• Large quantities of concentrated powders
• Food that has become putrid or badly spoiled

I am also cautious with resinous conifer foliage and strongly aromatic leaves. There are thousands of plant species in the world. There is no reason to gamble with something unknown when we have so many proven broadleaf choices!

Finally, more is not always better either.

There isn't one magic food when it comes to keeping isopods. 

A balanced diet starts with varied leaf litter, rotten hardwood, a nutritious organic substrate and a permanent calcium source. Protein, lichen, vegetables and other supplements can then provide additional nutrition and variety according to the needs of each colony. I personally enjoy experimenting with conditioned leaf litter and my mushroom-and-spirulina blend, but these should complement, not replace, the foundations of their diet.

Ultimately, feeding isopods starts with building the right enclosure, not buying the right packet of food. In nature, their food surrounds them in the form of decaying leaves, wood, fungi and microorganisms. That's what I aim to recreate in my cultures.