May 26, 2025

Isopod Guide – All the Tips to Get Started

Introduction

Terrestrial isopods, also known as woodlice, have gained popularity in recent years within the world of terrariums, specialized breeding, and the ecological management of microhabitats. Their ability to break down organic matter, aerate the substrate, and actively participate in nutrient recycling makes them key organisms in closed and bioactive systems. In addition, their variety of morphologies and colors has driven genetic selection and the development of new lines through selective breeding.

However, to maintain healthy and sustainable colonies, it is essential to understand their biological needs, the risks associated with improper practices, and the ethical and environmental challenges of breeding and trade. This guide addresses these aspects in depth, offering a solid foundation for those who wish to begin or refine their knowledge in the responsible care of terrestrial isopods.

Terrarium size and ventilation

Terrarium size is a key aspect when breeding isopods. It must be adapted both to the number of specimens and to the specific needs of the species. For example, in a small container, such as a shoe box, you can keep between 100 and 200 individuals of hardy species like Dairy Cow, Cylisticus murina or Armadillidium vulgare. In contrast, more delicate species require lower density and more space per individual.

A 20×10×10 cm terrarium can be suitable for housing around 100 isopods of common species, but this measurement does not fit all cases. Each species has different requirements depending on its size, behavior, and natural environment. That’s why it’s best to research the conditions needed by the species you plan to keep. Consulting with experienced breeders can also be very helpful.

Ventilation is another fundamental point. Good airflow inside the terrarium helps maintain suitable humidity levels, prevents stagnant air, and facilitates gas exchange. To control humidity, it is recommended to use a hygrometer. This not only improves environmental quality, but also prevents mold and other problems associated with poor ventilation.

Hygrometer, temperature and humidity

Having a hygrometer is very useful for monitoring the terrarium conditions. Some models, such as the Xiaomi hygrometer, can measure both humidity and temperature quite accurately. This makes it easier to maintain an environment suitable for the development and well-being of the isopods.

Temperature

The ideal temperature for most species is between 28–29 °C. In this range, isopods reproduce quickly and remain active. If the temperature rises to 31 °C, you may start to notice some losses. Conversely, if it drops to 23–25 °C, reproduction slows and may take an extra month to occur. At lower temperatures, between 16–20 °C, reproduction decreases even more, to about three months. And if the temperature falls to 10 °C, the isopods enter a state of hibernation.

Humidity

For isopods, it is ideal for the terrarium to maintain humidity of 80–90 %, always with good ventilation. If humidity exceeds 90 %, increase ventilation to avoid problems such as mold or lack of oxygen.

Watering the terrarium raises humidity levels, so you should adjust the amount of water according to the range you need. A simple way to control excess humidity is to add more ventilation holes.

It is also important to keep the sphagnum moss consistently moist, as it helps stabilize humidity. As for the substrate, it is usually kept constantly moist without drying out anywhere.

Lastly, remember that each isopod species may have different needs, so research their specific preferences to provide the best possible conditions.

Cork bark and dried sphagnum moss

Cork bark

Cork bark is an essential element in the terrarium, providing shelters where isopods can hide and feel secure. If you use flat bark, it’s best to place it with the darker, rougher side facing down, in contact with the substrate. This texture offers a better surface for isopods to climb and hide.

You can also use curved bark. These pieces often come as a tube, but they can easily be cut into three long strips. Thanks to their arched shape, they work very well as tunnels or caves, offering multiple hiding places in the enclosure.

Sphagnum moss

Dried sphagnum moss is another very useful component, as it helps maintain humidity in the terrarium. This is especially important for isopods, which breathe through gills located near the posterior end of their body. These gills need to stay moist to function properly, and the moss provides that ideal humid microenvironment.

Typically, sphagnum moss is placed on one side of the terrarium, taking up approximately 20 % of the total space. That way, isopods can move toward it when they need more humidity. It’s recommended to use Chilean sphagnum moss, as it is denser and retains moisture better than other varieties.

Substrate, nitrogen cycle, and ammonia control

Choosing the substrate

To keep isopods, you can use coco fiber with potting soil or peat-based compost as the substrate base. Ideally, maintain a substrate depth of 3–4 cm, sufficient for isopods to burrow and carry out their natural activities.

Nitrogen cycle and ammonia levels

The substrate preparation process is similar to “cycling” in aquaristics. When starting with new substrate, it is common for dangerous ammonia levels to accumulate, which can exceed 3 ppm. To avoid harming isopods, you need to allow nitrifying bacteria to establish, which transform ammonia into nitrite (NO₂) and then nitrate (NO₃), which are less toxic. This process can take about a month.

During this time, you can monitor cycling progress using two methods:

Method A: Observe the type of mold

The type of mold that appears in the substrate can give clues about ammonia levels:

White (cottony) mold: the substrate is very fresh (less than a week). Ammonia levels still high, above 3 ppm.
Green mold: indicates ammonia has dropped to around 1.5 ppm. Cycling is halfway.
Orange or yellow mold: levels have dropped below 0.5 ppm. It’s already safe to introduce isopods, but only in small numbers.

📌 For an enclosure the size of a shoe box, it is recommended to start with only 10 to 12 isopods.

Note: This method may vary if you use substrates with additives, such as coco fiber.

Method B: Using an ammonia test kit

If you prefer a more precise method, you can use an ammonia test kit. Here’s how:

Take 5 ml of substrate.
Add 10 ml of clean water and shake well.
Let the debris settle.
Draw off 5 ml of the clear water from the surface.
Run the test on that water.

🔁 Important: multiply the result by 2, since you made a dilution with 10 ml instead of the 5 ml most kits use.

As long as ammonia levels are detectable, do not introduce isopods into the enclosure.

Tips for a more controlled cycling

You can prepare the substrate in a separate container before using it in the main terrarium.
Add soil and water with minimal ventilation and let it cycle for a month.
Once transferred to the final enclosure, wait 3–4 days more before introducing the isopods.

Limestone and calcium sources in the enclosure

Is limestone necessary?

Traditionally, many Cubaris keepers have included limestone in their enclosures. However, our tests indicate that limestone is not strictly necessary for isopod well-being.

Its main function in the enclosure is thermal, acting as a cool surface in humid environments. Thanks to its ability to stay at a lower temperature, limestone helps isopods regulate their body temperature when the environment becomes too warm.

⚠️ Avoid handling isopods for prolonged periods. Our body temperature (around 37 °C) is too high for them and can cause thermal stress.

Calcium and exoskeleton development

Isopods require calcium to form a healthy exoskeleton. A calcium deficiency can lead to cannibalism, as individuals will seek to obtain it from their companions.

Cuttlebones (cuttlefish bone) and other solid calcium sources are highly recommended because:

They provide a stable, continuous source of calcium.
They do not alter humidity or the substrate balance.

By contrast, powdered calcium can present drawbacks:

It tends to clump on contact with moisture.
It can dry out the substrate if overused.

✅ It is recommended to use powdered calcium with moderation and controlled dosage, or to prefer solid sources such as cuttlebone to avoid altering the microenvironment.

Classification and main characteristics of terrestrial isopods

Terrestrial isopods can be classified into three main groups, each with specific characteristics in terms of breeding difficulty, reproduction rate, growth, and longevity:

A) Armadillidium

This group is ideal for beginners due to its hardiness and ease of care.

Hardiness: High. They tolerate moderate variations in humidity and temperature well.
Reproduction: Fast, although the growth rate of the young is slower.
Behavior: Voracious and active, especially in the presence of decaying plant matter.
Recommended for: Getting started with isopods without strict environmental requirements.

B) Porcellio

Includes a wide diversity of species, some easy to keep and others much more demanding.

Species variety: Broad. From easy species like Porcellio laevis “Dairy Cow” to advanced species like Porcellio expansus and Porcellio bolivari.
Reproduction and growth: Fast. At optimal temperatures (~28 °C), juveniles can reach maturity in approximately 45 days.
Lifespan: Shorter than Armadillidium. Females usually have 2–3 litters before dying.
Difficulty level: Intermediate to advanced, depending on the species.

C) Cubaris

Considered the most demanding group in terms of maintenance and reproduction.

Sensitivity: High. Requires a well-controlled microhabitat in terms of humidity, ventilation, temperature, and substrate quality.
Size and reproduction: Young are small and their development is noticeably slow.
Difficulty level: High. It is recommended to gain prior experience with Armadillidium and Porcellio before keeping species of this genus.
Popular examples: Cubaris murina, Cubaris sp. “Panda King”, Cubaris sp. “Rubber Ducky”.

Pests and commensals in isopod colonies

In controlled environments where isopods are kept, both harmful species and beneficial cohabitants commonly appear. Correctly identifying each type of organism is essential to maintain a healthy, functional ecosystem.

🛑 Pests: organisms that pose a risk to isopods

A) Snails
Some snail species can prey on freshly molted or juvenile isopods, particularly attacking their exoskeleton to obtain calcium. Their feeding strategy relies on constant pressure and high numbers.

B) Earthworms
Worms, especially African species (Eudrilus eugeniae and similar), can ingest isopod juveniles. However, some species such as Malaysian blue worms can cohabit without major conflicts and, in some cases, are used as natural population control.

C) Spiders
Although they do not attack isopods directly, spiders build functional webs to trap small insects such as mosquitoes or springtails. Isopods can become accidentally trapped and die as collateral prey.

D) Flatworms (Planaria)
They are active predators of juveniles. They move across the ground in search of prey and can have a severe impact if not controlled.

E) Parasitic mites
Although most mites are harmless or beneficial, there are parasitic species, slow-moving, that shelter under bark or limestone. Initially they consume organic debris, but over time they begin to feed directly on isopods, especially juveniles.

F) Mosquitoes (larvae)
Mosquito larvae can proliferate if there is excess humidity and undecomposed organic matter. They feed on food leftovers (such as fish food), and their presence indicates a poorly cycled habitat.

Recommendation: reduce humidity in the feeding area and use Bacillus thuringiensis israelensis (BTI) granules in the watering, as they do not affect isopods.

✅ Commensals: beneficial or neutral organisms

A) Springtails
Detritivores that control mold growth and remove organic residues. However, their overpopulation can attract predatory mites. For novice keepers, it is recommended to avoid introducing springtails until the substrate is well cycled.

B) Predatory mites
They feed on springtails and other microarthropods. They are nocturnal and shelter in the substrate during the day. Their presence usually indicates a balanced ecosystem or one in a phase of biological regulation.

C) Millipedes (Diplopoda)
Small millipedes coexist without problems with isopods. They are detritivores specialized in decaying plant matter and contribute to substrate fragmentation.

D) Centipedes (Chilopoda)
In these habitats, very small species are usually found which, to date, have not shown predatory behavior toward isopods.

Water pH and using tap water

The water pH used in enclosures is a key factor in isopod health and development. These species perform better in slightly alkaline environments, with an ideal pH range between 8.0 and 8.5.

Although many keepers successfully use untreated tap water, it is important to consider local particularities:

In urban areas, tap water tends to have a neutral or slightly alkaline pH due to municipal treatment processes.
In rural areas or homes with wells or autonomous systems, pH can vary considerably. In some cases it may be acidic (pH < 7.0), which poses a risk to colony stability.

Prolonged exposure to low-pH water can affect exoskeleton calcification and alter the substrate’s microbial balance, leading to a progressive decline in population.

Practical recommendations

Use boiled, rested water for at least 12 hours to remove chlorine and chloramines.
Measure your tap water pH if you don’t know its composition, especially if you experience unexplained deaths or poor growth.
If the pH is low, you can safely raise it with:
- Fragments of crushed coral, oyster shells, or
- Limestone, which can also act as a cooling point (see the corresponding section).
- Commercial additives for hard-water aquariums (used with caution).

Feeding isopods: nutritional balance and reproduction

An appropriate diet is essential for colony development, longevity, and reproductive success. Feeding should be based on a balanced combination of animal protein, fresh plant matter, and targeted supplementation such as beta-carotene.

A) Animal protein

Animal protein is essential for exoskeleton formation, soft tissue development, and reproductive success, especially in females.

Recommended sources:
- Fish food (pellets or flakes)
- Unsalted dried fish (e.g., previously washed cod)
- Insectivore or reptile kibble (high in protein)

These sources should be offered in small amounts and removed if not consumed within 24–36 hours to avoid proliferation of mosquito larvae or mites.

B) Vegetables and greens

Isopods readily consume soft plant matter. Vegetables provide not only moisture and fiber but also micronutrients and bioactive compounds.

Examples of suitable vegetables:
- Zucchini
- Peas
- Bauhinia leaves (Bauhinia sp.), known for their high mineral content
- Cucumber, Swiss chard, carrot, spinach (in moderate amounts)

It’s advisable to vary plant sources to cover a broader nutritional spectrum and avoid deficiencies.

C) Beta-carotene supplementation

Beta-carotene not only enhances the coloration of many ornamental species but also strengthens the immune system and can positively influence fecundity.

Recommended form: Beta-carotene powder (available on platforms like Taobao, Amazon, etc.)
Avoid: Oil-based capsules, since isopods cannot efficiently process concentrated lipids and they may contaminate the substrate.

D) Feeding frequency and quantity

Food should be provided in moderate amounts, enough to be consumed within 24–36 hours. Excess food:

Favors the proliferation of mosquito larvae
Increases the risk of mites and fungi

Reproductive observation (case study)

In a colony of lemon blue isopods fed exclusively with vegetables, growth from 6 to 60 individuals was observed, but with a notable sex imbalance (57 males and only 3 females). After changing the diet to 50% animal protein and 50% vegetables, the sex ratio balanced markedly, indicating that the presence of animal protein is crucial for female reproductive success.

Maintenance and environmental management of isopod colonies

Regular maintenance is essential to ensure a stable, healthy environment conducive to isopod reproduction. Care tasks focus mainly on humidity control, feeding, and substrate monitoring.

A) Maintenance frequency

The basic maintenance cycle should be performed every 2–3 days, adjusted according to factors such as:

Ambient temperature (the higher the temperature, the higher the evaporation)
Level of ventilation (systems with good ventilation will require more frequent watering)
Isopod species (some, such as Cubaris, require higher humidity and stability)

B) Hydration

Humidity is critical for both breathing and molting.

Recommended method: Mist water with a fine sprayer onto the substrate (not directly on the isopods)
Indicative frequency: Every 2 days in ventilated systems; up to every 3–4 days in closed or high-humidity systems
Differentiated zones: It’s advisable to maintain a wetter area and a drier area within the habitat so isopods can self-regulate

C) Feeding

Check and replenish food according to the guidelines described. Any leftovers not consumed within 24–36 hours should be removed to prevent pest proliferation or the accumulation of decomposing matter.

D) Detecting environmental imbalance

A critical sign of poor maintenance is widespread mortality affecting individuals of all ages (adults, subadults, and juveniles). This phenomenon usually indicates:

Accumulation of toxic compounds in the substrate, especially ammonia from decomposing organic matter and droppings.

Corrective measures:

Partial substrate change (remove at least 30–50%)
Temporarily increase ventilation
Reduce feeding for 48–72 hours
Assess population load relative to available space

Wild-caught vs. captive-bred

The origin of isopods significantly affects their survival, adaptation, and reproduction. In the context of countries with restrictions such as Singapore, where isopod imports are prohibited, it is especially important to understand the differences between wild-caught specimens and those bred in captivity.

A) Wild-caught isopods

These specimens come directly from their natural environment, generally collected intensively by third parties.

High mortality rate: Only 3–5 out of 10 captured individuals manage to survive the capture, storage, and transport process.
Main causes of mortality:
- Inadequate storage conditions: Excess density and lack of air renewal.
- Physiological stress due to capture and handling.
- Ammonia exposure: Observational studies have shown that 10 isopods in a closed container can raise ammonia concentration to 3 ppm in 24 hours, a level that damages gills and internal organs.
Sex imbalance: Survivors often show a male majority, as females are more sensitive to stress and deteriorating conditions.
Complicated adaptation: Their transition to an artificial environment is often difficult due to differences in microhabitat and diet.

B) Captive-bred isopods

From breeding lines established under controlled conditions, captive-bred isopods offer multiple advantages:

High survival rate during transport and acclimation.
Better adaptation to diet, humidity, and artificial light cycles.
Lower health risk, as they are usually free from external parasites or pathogens.
Local availability: In many regions there are keepers and breeders who offer already adapted specimens, along with species-specific advice and support.

Recommendation

For beginner or intermediate keepers, it is strongly recommended to opt for captive-bred specimens, especially from local suppliers. This choice not only improves the chances of success in breeding but also supports responsible and sustainable practices.

Uses and purpose of isopods

Isopods play a fundamental role in closed ecosystems and in the sustainable management of organic waste, thanks to their detritivorous behavior and reproductive capacity.

1. Efficient decomposers

Thanks to their accelerated metabolism and opportunistic feeding habits, isopods can be more effective than earthworms at decomposing organic matter. They are especially efficient at fragmenting and recycling dry leaves, decaying wood, and soft plant residues.

High consumption rate
Ability to break down partially lignified materials
Greater tolerance to variations in humidity and temperature

2. Natural fertilizer

The substrate used by isopods can be reused directly as organic fertilizer or a growing medium. This substrate is enriched with:

Nitrogen compounds in higher concentrations than substrates used by worms.
Micronutrients from chitin residues and shed exoskeletons.
Beneficial microbiota that improves soil structure.

3. Ecological maintenance in terrariums/vivariums

Isopods are commonly used as part of the “clean-up crew” in closed environments with reptiles, amphibians, or tropical plants:

They consume animal droppings, uneaten food, and dead leaves.
They aerate the top layer of the substrate, reducing compaction and improving root oxygenation.
They prevent mold buildup, especially when cohabiting with springtails.

4. Use as a food source

Although they have a high calcium content, isopods have a low protein content, which makes them less attractive as a primary prey item in animal diets.

They can be offered as an occasional supplement for some small amphibians or reptiles.
Their hardness and low nutritional value limit their use as an exclusive food source.

5. Safety and compatibility

Isopods do not pose a risk to other pets, as they are neither aggressive nor known transmitters of zoonotic diseases. They are compatible with most species that inhabit tropical or temperate terrariums.

Travel abroad and how to ensure isopod survival

International transport of isopods is a logistical challenge that requires specific conditions to minimize physiological stress and ensure viability during transit. Below are the main recommended measures:

1. Pre-shipment preparation

A conditioning period of at least 2–3 weeks allows isopods to build energy reserves and develop greater stress resistance:

Rich and balanced diet: Increase the proportion of animal protein (e.g., fish food or unsalted dried fish) and fresh vegetables.
Additional beta-carotene: Supports immune status and overall metabolism.
Environment with stable temperature and adequate ventilation, ideally with air conditioning if the region is warm.

2. Preparing the travel container

During transport, it is essential to reduce risk factors associated with dehydration, ammonia buildup, and overheating:

Moisture source: Place water beads (hydrated polymer crystals) on sphagnum moss to maintain steady, safe humidity without waterlogging.
Reduced ventilation: Limiting the number of ventilation holes helps conserve internal humidity and slow evaporation. However, maintain minimal passive ventilation to avoid CO₂ buildup.
Thermal insulation: Use expanded polystyrene thermal boxes or reflective wraps if sharp temperature changes are expected during transit.

3. Prior evaluation via pilot test

Before the actual shipment, it is advisable to carry out a simulated travel trial with a small sample:

Reproduce the transport conditions for a period similar to the estimated shipping time.
Evaluate survival, mobility, and behavior after the trial.
Adjust humidity, ventilation, or population density based on the results.

4. Additional considerations

Do not overpopulate the container: It has been shown that 10 isopods can raise ammonia levels to 3 ppm in 24 hours, which can damage their gills.
Pack less than 24 h before shipping: This is standard practice among experienced breeders to minimize exposure to accumulated ammonia.
Avoid thermal shocks: On long trips or when crossing regions with extreme climates, consider using cold gel packs or thermal bags.

Overwhelming numbers and overpopulation control

Excessive population growth of captive isopods can pose a logistical and ecological problem if not managed properly. Below are ethical and sustainable methods for population control:

1. Responsible redistribution

A priority option is to share, trade, or donate surplus specimens to other keepers, especially beginners who are just starting out. This practice fosters community cooperation and promotes responsible breeding.

2. Ethical culling and use

If redistribution is not possible, you can resort to culling by freezing, considered an ethical, low-stress method:

Place the isopods in a container with minimal ventilation.
Put the container in the freezer, where they will die within up to 24 hours.
Afterwards, the bodies can be used as:
- A protein source for other isopods or detritivores.
- Organic fertilizer rich in calcium and nitrogen for plants.

3. Reducing reproductive stimulus

You can slow the reproductive rate by adjusting certain environmental factors:

Reduce the availability of food and water, limiting ideal conditions for reproduction.
Maintain lower temperatures within the species’ tolerance range.

4. Introducing natural competitors

You can add a controlled population of African worms (Eudrilus eugeniae) to the system:

They compete for resources and oxygenate the substrate.
They consume organic residues and feces, helping limit isopod proliferation without compromising system health.

5. Environmental warning: never release into the wild

It is absolutely critical not to release isopods into natural environments. Even if their impact seems low, introducing non-native species can disrupt fragile ecosystems.

All actions should be based on environmental responsibility and respect for local biodiversity.

Genetics, morphology, and selective breeding in isopods

Selective breeding of isopods allows you to obtain individuals with specific color patterns, shapes, or behavioral traits by leveraging their genetic variability. This process requires patience, careful observation, and proper isolation of genetic lines.

1. Isolating spontaneous genes (“oddballs”)

Occasionally, individuals with atypical morphological or chromatic characteristics emerge, commonly known as “oddballs.” These traits may be caused by desirable genetic mutations. To isolate and fix these genes in a stable line, the following is recommended:

If the “A” individual is male:

Separate “A” from the main colony to avoid uncontrolled crossings.
Pair him with virgin females, ideally from the same generation or clutch. Some species (e.g., pale blue or glossy alligator varieties) can store sperm, so females with no recent reproductive history should be used.
Remove the females after the offspring are born.
Observe subsequent generations:
- If the gene is recessive, it may take two or more generations to express.
Select individuals with the desired traits and continue breeding with them.

If the “A” individual is female:

Isolate her immediately from the original colony.
Introduce males from the same clutch or genetic line.
Once pregnant, remove all males to avoid subsequent crossings.
Continue breeding and select offspring that express the desired trait.
Repeat the process over several generations to stabilize the mutation.

2. Selective breeding to refine patterns or colors

This method seeks to accelerate the expression of certain patterns or color hues already present in a population, such as the intensity of white on the head or tail of a “Panda King.”

Steps for successful selective breeding:

Select the specimens closest to the desired pattern.
Isolate these individuals from the original colony.
Confirm the presence of fertile males and females (it is advisable to keep multiple pairs).
Observe the offspring:
- If improvements are observed, continue with the improved specimens.
- If there is no progress, continue the cycle until visible improvements emerge.
Cull or remove individuals that do not express the desired traits or show morphological regression.
Repeat the process over multiple generations, gradually refining the target traits.

Ethical and technical considerations

Always keep detailed records of crossings and observed phenotypes.
Ensure animal welfare, avoiding extreme inbreeding or inadequate breeding conditions.
Stabilized lines should be kept isolated to avoid genetic contamination.

Join and save money