Isopods What are They and How are They Used

What Are Isopods?

Isopods are small, crustacean invertebrates belonging to the order Isopoda. They are related to crabs, lobsters, and shrimp, and are found in a variety of environments, including marine, freshwater, and terrestrial ecosystems. Terrestrial isopods, often referred to as “pill bugs” or “woodlice,” are commonly used in bioactive terrariums.

Characteristics of Isopods

  1. Body Structure:
    • Isopods have a segmented exoskeleton, typically with seven pairs of legs and two pairs of antennae.
    • Their body is divided into three main parts: the head, thorax, and abdomen.
  2. Size:
    • Terrestrial isopods range in size from a few millimeters to about 2 centimeters, depending on the species.
  3. Behavior:
    • Isopods are detritivores, meaning they feed on decaying organic matter, including dead plant material, fungi, and decomposing wood.
    • They are generally nocturnal and prefer moist environments.

Uses of Isopods in Terrariums

  1. Bioactive Substrate Maintenance:
    • Benefit: Isopods are integral to maintaining a healthy bioactive substrate by breaking down organic waste.
    • Function: They consume decaying plant matter, animal feces, and other detritus, converting it into nutrient-rich soil that benefits plant growth.
  2. Natural Clean-Up Crew:
    • Benefit: By consuming organic waste and mold, isopods help prevent the buildup of harmful bacteria and fungi.
    • Function: This natural waste management reduces the need for frequent manual cleaning, contributing to a self-sustaining ecosystem.
  3. Soil Aeration:
    • Benefit: As isopods burrow and move through the substrate, they help aerate the soil.
    • Function: This promotes better water infiltration and root growth for plants.
  4. Nutrient Cycling:
    • Benefit: Isopods play a crucial role in nutrient cycling by breaking down complex organic materials into simpler compounds.
    • Function: These nutrients are then more readily available for uptake by plants, promoting a healthy and balanced ecosystem.
  5. Feeding Source:
    • Benefit: Isopods can serve as an additional food source for some small reptiles and amphibians.
    • Function: Providing a natural diet option that can enhance the dietary diversity for the primary inhabitants of the terrarium.

Setting Up Isopods in a Bioactive Terrarium

  1. Substrate Preparation:
    • Use a bioactive substrate mix that includes organic soil, leaf litter, and decomposed wood. Ensure the substrate is moist but not waterlogged.
  2. Adding Isopods:
    • Introduce a colony of isopods to the terrarium. Common species include Armadillidium vulgare (pill bugs) and Porcellio scaber (rough woodlice).
    • Scatter the isopods across the substrate, providing hiding places with pieces of bark or leaf litter.
  3. Maintaining the Environment:
    • Keep the substrate moist to support the isopods’ moisture requirements. Mist the terrarium regularly, but avoid overwatering.
    • Maintain proper temperature and humidity levels suitable for both isopods and the primary inhabitants.
  4. Feeding Isopods:
    • Supplement their diet with occasional pieces of fruit, vegetables, and decomposing leaves to ensure a balanced diet.
  5. Monitoring and Population Control:
    • Regularly check the isopod population and health. A thriving colony will indicate a healthy, balanced terrarium environment.
    • If the population becomes too large, you can transfer some isopods to another terrarium or share them with other hobbyists.


Isopods are beneficial inhabitants of bioactive terrariums, providing essential ecological services such as waste decomposition, soil aeration, and nutrient cycling. By incorporating isopods into your terrarium, you create a more natural and self-sustaining environment that supports the health and well-being of both plants and animals. Proper care and maintenance of the isopod population will ensure a thriving, balanced ecosystem within your terrarium.