Dwarf White Isopods (Trichorhina Tomentosa)

Dwarf White Isopods (Trichorhina tomentosa) are the workhorses of the bioactive hobby. Tiny, prolific, and utterly dedicated to their cleanup duties, these miniature isopods have earned their reputation as essential "tank janitors" for terrariums and vivariums worldwide.

At under 5mm fully grown, they're among the smallest isopod species available - less than half the size of most common isopods. But what they lack in size, they more than compensate for with sheer numbers and an impressive appetite for waste. A thriving colony of Dwarf Whites will efficiently process animal droppings, decaying plant matter, uneaten food, mould, and organic debris, keeping your enclosure clean and healthy.

Native to the tropical forests of Central and South America, these soft-bodied isopods thrive in warm, humid environments. Their bright white colouration makes them easy to spot against dark substrate - useful when you want to check on your colony's progress.

A Glimpse

Origin: Central and South America

Scientific Name: Trichorhina tomentosa

Difficulty Level: Very Easy

Size: 2-5mm (one of the smallest species)

Lifespan: Up to 3 years

Temperature: 21-29°C (room temperature is fine)

Humidity: 70-80%

Rarity: Very Common

An Overview

Dwarf White Isopods occupy a unique niche in the hobby. Unlike the larger, more colourful species kept primarily for display, Trichorhina tomentosa are valued almost entirely for their practical utility. They're the invisible maintenance crew working tirelessly beneath the surface of your bioactive setup.

Their claim to fame is their remarkable breeding ability. Dwarf Whites are parthenogenetic - every individual is female and can reproduce without mating. This means a single isopod can establish an entire colony. Combined with their prolific breeding rate (females can produce 30+ offspring monthly), populations explode rapidly under good conditions. A small starter culture can become thousands within months.

This reproductive strategy makes them incredibly effective as a cleanup crew. Their numbers quickly scale to match the waste production in any enclosure, and they can outcompete pest species like grain mites and wood mites by sheer population pressure.

They're also popular as feeder insects for smaller reptiles and amphibians. Their tiny size makes them perfect for dart frogs, small geckos, and froglets - animals too small to eat larger isopod species. They're soft-bodied and nutritious, providing a natural food source that also performs cleanup duties between being eaten.

Their burrowing nature means you'll rarely see them on the surface during the day. They prefer to stay hidden within substrate and leaf litter, emerging mainly to feed. This makes them an "invisible" cleanup crew - they do their work unseen.

Basic Care

Dwarf White Isopods are among the easiest isopods to keep, tolerating a wide range of conditions and requiring minimal attention once established.

Temperature should be maintained between 21-29°C (70-85°F). They thrive at typical room temperatures without supplemental heating. Warmer temperatures within this range encourage faster breeding.

Humidity is important - aim for 70-80%. As tropical species, they prefer consistently moist conditions. Unlike some isopod species that need a moisture gradient, Dwarf Whites do well with uniformly damp substrate. However, avoid waterlogging - good drainage is essential.

Ventilation requirements are minimal. Unlike larger isopods that prefer good airflow, Dwarf Whites tolerate lower ventilation. A few small holes for air exchange are sufficient. This actually makes them easier to maintain, as humidity is easier to keep stable.

Enclosure size can be small - their tiny size means even compact containers can house large colonies. They don't climb, preferring to burrow, so lid security is straightforward.

They're remarkably adaptable and forgiving of imperfect conditions, making them genuinely beginner-friendly. If you can maintain basic humidity and temperature, they'll thrive.

Feeding

Dwarf White Isopods are detritivores with unfussy appetites. They'll consume virtually any decomposing organic matter, making them exceptionally effective cleanup crew members.

Primary foods (should always be available):

Hardwood leaf litter (oak, beech - essential for both food and habitat)

Decaying driftwood and softwoods

Fungi and mould (they actively consume these)

Animal droppings (in bioactive setups)

Supplementary foods (offered occasionally):

Vegetable scraps - carrots and cucumbers are favourites

Fruit scraps (use sparingly to avoid mould issues)

Fish flakes or dried shrimp (protein source)

Decaying plant matter

Calcium supplementation is beneficial though less critical than for larger species. Crushed eggshells or cuttlebone can be offered.

Their appetite is remarkable for their size. Despite being tiny, colonies consume substantial amounts of organic matter. This is precisely why they're so effective as cleanup crews - they process waste rapidly and efficiently.

In bioactive enclosures, they'll naturally consume animal faeces, shed skin, uneaten feeder insects, fallen plant material, and any developing mould. They turn waste into nutrients that benefit plants and soil health.

Be mindful not to overfeed fresh foods, as excess can create mould problems in humid environments. Leaf litter and decaying wood should form the bulk of their diet.

Appearance and Behaviour

Dwarf White Isopods are genuinely tiny. Adults reach only 2-5mm in length (under 1/4 inch), making them one of the smallest isopod species available. For context, they're roughly the size of a grain of rice.

Their colouration is uniformly white to cream, with soft, somewhat translucent exoskeletons. Unlike the hard, calcified shells of Armadillidium species, Dwarf Whites have pliable bodies. Their white colour provides strong contrast against dark substrate, making them relatively easy to spot despite their small size.

Their bodies are oval-shaped and segmented, typical of isopods, with multiple pairs of legs. They lack the ability to roll into a ball (conglobate) like pill bug species.

Behaviourally, Dwarf Whites are dedicated burrowers. They spend most of their time beneath the substrate surface or hidden within leaf litter, rarely venturing into the open during daylight hours. This makes them largely invisible in most setups - you'll know they're working by the results rather than by seeing them.

They're nocturnal, becoming more active at night when they emerge to feed. If you want to observe them, checking after dark with a red light works well.

Their parthenogenetic reproduction (all-female, asexual breeding) is their most remarkable trait. Every adult can produce offspring without mating, leading to rapid population growth. A single female can produce 30+ babies monthly, and those offspring mature quickly to begin reproducing themselves.

They're completely harmless - they don't bite, sting, or carry diseases. They're docile and show no aggression toward enclosure inhabitants.

Habitat

Dwarf White Isopods are native to the tropical and subtropical forests of Central and South America, where they inhabit moist leaf litter on forest floors.

Enclosure options:

Small plastic containers work perfectly for culturing

Any terrarium or vivarium for bioactive use

Front-opening or removable-top containers for easy access

Minimal space required due to their tiny size

Temperature: 21-29°C (70-85°F). Standard room temperature is ideal - no special heating required.

Humidity: 70-80%. Consistently moist conditions are preferred.

Ventilation: Minimal. A few small holes for air exchange are sufficient. Low ventilation actually helps maintain humidity.

Substrate depth: A few centimetres is adequate. They burrow but don't require extremely deep substrate like some larger species.

Lighting: None required. They're nocturnal and prefer dark, damp conditions.

They're often used alongside springtails in bioactive setups. The two species complement each other perfectly - springtails target smaller debris and mould while Dwarf Whites handle larger organic matter. Together, they create a comprehensive cleanup crew.

Note: While excellent with most animals, Dwarf Whites can stress certain burrowing invertebrates like Therea roaches and some large Spanish Porcellio species. Their persistent presence seems to disturb these animals. For most reptile and amphibian setups, however, they're ideal companions.

Substrate Mix

Dwarf White Isopods are less demanding about substrate than many species, though they still benefit from an appropriate mix.

Simple culture substrate:

Coconut coir (Dwarf Whites are one of the few isopods that thrive in pure coco coir)

Peat moss

Organic topsoil

Any combination of the above

Enhanced bioactive substrate:

ABG mix or similar tropical substrate

Coconut coir base

Earthworm castings (adds nutrients)

Charcoal (aids drainage)

Essential additions:

Generous hardwood leaf litter (both food and habitat)

Decaying wood pieces or cork bark

Hiding spots (bark, wood, leaf coverage)

Unlike many isopods that struggle with plain coconut coir, Dwarf Whites actually thrive in it - as long as leaf litter and other botanicals are provided. This makes substrate preparation particularly easy.

Maintain consistent moisture throughout - Dwarf Whites prefer uniformly damp conditions rather than the moisture gradient required by some species. The substrate should feel damp but not waterlogged. Ensure adequate drainage to prevent standing water.

pH should ideally range between 6.2-7.5, with water hardness of 5-11 dGH if you're monitoring these parameters (though they're tolerant of variation).

Breeding

Dwarf White Isopods are among the easiest isopods to breed - in fact, stopping them from breeding would be the challenge.

Their parthenogenetic reproduction means every adult can produce offspring independently. No males exist in this species; females essentially clone themselves. This reproductive strategy results in exponentially growing populations.

Breeding rate: Females can produce 30+ offspring monthly. Juveniles reach maturity in 4-6 weeks, at which point they begin reproducing themselves. This creates compound growth - populations can explode from a small starter culture to thousands within months.

Breeding conditions: Maintain humidity at 70-80%, temperatures at 21-29°C, abundant leaf litter, and some protein supplementation. Beyond these basics, breeding happens automatically.

Females carry eggs in a brood pouch and produce egg capsules (oothecae) containing 15-20 fertilised eggs. Each female can produce up to five oothecae in her lifetime.

Seasonal patterns: Breeding may be initiated more in autumn/winter months, though under stable captive conditions they breed year-round.

Their prolific breeding makes them self-sustaining in bioactive setups. Once established, a colony will maintain itself indefinitely, with populations naturally adjusting to match available food (waste production).

For culturing purposes, starting with 50-100 individuals provides a strong foundation that will rapidly multiply into a thriving colony.

Uses in Bioactive Setups

Dwarf White Isopods excel in several roles:

Cleanup Crew: Their primary function. They efficiently process animal droppings, shed skin, fallen plant material, uneaten food, and developing mould. Their numbers scale to match waste production.

Substrate Aeration: Their burrowing activity keeps substrate fresh and prevents compaction, encouraging healthy plant root growth and preventing anaerobic zones.

Feeder Insects: For small reptiles and amphibians (dart frogs, small geckos, froglets), they provide a nutritious food source. Their soft bodies are easily digestible.

Mite Competition: Thriving Dwarf White populations can outcompete pest mite species (wood mites, grain mites) through sheer numbers, helping prevent infestations.

Symbiotic Partners: They work excellently alongside springtails and other isopod species, each handling different aspects of waste processing.

They're suitable for most reptile and amphibian enclosures, particularly those requiring high humidity. Their small size means they won't disturb inhabitants, and they're too tiny to pose any threat to animals.