Quick answer: For most bioactive terrariums the best clean-up crew is a culture of springtails (such as Folsomia candida) plus a small, non-aggressive isopod like dwarf white isopods (Trichorhina tomentosa). Arid builds swap in drought-tolerant isopods such as Porcellio laevis or Porcellionides pruinosus. Add the crew to a seeded, damp soil at least two to four weeks before the animal goes in, and feed them lightly until the enclosure is producing its own waste.
This page replaces two older posts on choosing a crew and why crews matter, so everything is in one place. For the deeper biology of springtails and isopods, see our springtails and isopods guide. Here we focus on choosing the right crew for your build and keeping it alive.
Why a clean-up crew matters
A bioactive terrarium is "bioactive" because something living breaks down the waste. Without a crew, faeces, shed skin, uneaten feeders and dead plant matter sit on the surface and grow mould or bacteria, and the enclosure starts to smell. With a healthy crew:
- Waste is processed quickly. Springtails and isopods eat mould, frass and decaying matter, often within days.
- Mould stays in check. A white fuzz on new wood is normal; springtails graze it down. Our mould guide explains what is normal and what is not.
- Soil stays aerated. Burrowing isopods turn the top layer, which helps prevent anaerobic pockets and the sour smell covered in why does my bioactive enclosure stink.
- Plants get fed. Crew droppings return nutrients to the soil for roots to use.
- You clean less. You still spot-clean large waste, but full substrate changes become rare.
The core crew: springtails
Springtails (Collembola) are tiny six-legged hexapods that eat mould and fungal growth. They breed quickly, stay small enough that almost no animal can hurt them, and work in the tight spaces isopods cannot reach. Two species dominate the hobby:
- Temperate springtails (Folsomia candida): white, very easy to culture, happiest at normal room temperature and in damp soil. The default for most builds.
- Silver springtails (Sinella curviseta): slightly larger and more tolerant of a drier surface, which makes them useful in semi-arid builds with a damp lower layer.
Tropical "pink" and "orange" springtails are also sold, but identification is often loose, so buy from a breeder who can tell you what they actually have.
Isopods: the heavy lifters
Isopods are terrestrial crustaceans. They eat leaf litter, wood, faeces and dead feeders, and many species burrow. Choose by size, humidity needs and how much they might compete with or bother your animal.
- Dwarf white isopods (Trichorhina tomentosa): tiny, all-female (they reproduce without males), stay in the soil and leaf litter. Ideal for dart frogs, small geckos and tarantulas.
- Powder orange and powder blue isopods (Porcellionides pruinosus): fast breeders, active on the surface, tolerate a wide humidity range.
- Little sea isopods (Cubaris murina): medium-sized, tropical, roll into a ball. Good in humid builds for larger animals.
- Dairy cow isopods (Porcellio laevis): large, hardy and very fast-breeding. Excellent for semi-arid and bigger reptile enclosures, but can nibble on tender plants and stressed or moulting animals if underfed.
- Giant canyon isopods (Porcellio dilatatus): bulky and tolerant of drier conditions; a solid choice for larger arid builds.
Best crew by build type
| Build | Springtails | Isopods | Notes |
|---|---|---|---|
| Dart frogs, small tropical frogs | Folsomia candida | Dwarf white, powder orange | Springtails double as a food source for froglets. |
| Crested and gargoyle geckos | Folsomia candida | Dwarf white, Cubaris murina, powder orange | Fruit diet waste needs a strong crew; remove old food dishes. |
| Ball pythons, boas, larger tropical reptiles | Folsomia candida | Cubaris murina, Porcellio laevis, dwarf white | Big waste loads: spot-clean the bulk and let the crew finish. |
| Leopard geckos, bearded dragons (semi-arid) | Sinella curviseta | Porcellio laevis, P. dilatatus, powder orange | Keep one corner and the lower soil damp so the crew survives. |
| Terrestrial and burrowing tarantulas | Folsomia candida | Dwarf white | Small, soil-dwelling species only, to avoid disturbing moults. |
| Arboreal tarantulas | Folsomia candida | Dwarf white (optional) | Bolus leftovers often lodge in webbing up high; remove by hand. |
| Plant-and-moss-only terrariums | Folsomia candida | Usually none, or dwarf white | Springtails handle mould on new moss and wood. |
Other useful crew members
- Earthworms: great soil aerators in large, deep, damp builds. Many keepers use small red wigglers or native species from their garden; garden worms are a grey area because of hitchhiking pests, so cultured worms are safer.
- Beetles: blue death-feigning beetles (Asbolus verrucosus) work in very dry enclosures where isopods struggle.
- Millipedes: small species such as bumblebee millipedes process leaf litter and wood in humid builds, but they are better as display animals than true crew.
Avoid adding feeder insects as a "crew". Crickets and mealworms left loose will chew on sleeping or moulting animals.
How many to add
There is no exact number, because the crew will grow to match the food supply. As a practical starting point:
- Small builds (up to 45 × 45 × 45 cm): one springtail culture and 10 to 20 small isopods.
- Medium builds (around 90 × 45 × 45 cm): two springtail cultures and 20 to 30 isopods, ideally two species with different habits (one surface, one burrowing).
- Large builds (120 cm and up): two or three springtail cultures and 30 to 50 isopods, plus a top-up after the first couple of months.
In Canada, live springtail cultures from hobby breeders typically cost about $10 to $20 CAD, and common isopods about $15 to $40 CAD for a starter group. Rare Cubaris morphs cost much more but are no better at cleaning. One Bioactive does not sell live cultures; buy from local breeders, reptile expos or hobby groups, and never collect native wild invertebrates from parks or protected areas.
Setting the crew up to succeed
- Start with living soil. A quality bioactive mix such as Jurassic ABG Terrarium Mix (or the Semi-Arid Blend for dry builds) gives the crew structure and moisture.
- Add leaf litter. Isopods eat it and hide under it. Oak and magnolia break down slowly; see our leaf litter collection and the leaf litter comparison.
- Give them cover. A piece of cork bark flat on the soil becomes a humid refuge and breeding site.
- Wait before adding the animal. Two to four weeks lets populations establish before anything can hunt them.
- Feed lightly at first. A pinch of fish flakes, a slice of vegetable or a little dry yeast for springtails every week or two, removed if it moulds heavily.
Culturing your own crew
A backup culture means you never have to rebuy after a crash.
- Springtails: a plastic tub with a few small air holes, a layer of charcoal or damp coco fibre, and a few grains of dry rice or baker's yeast. Keep it damp, not flooded, at room temperature. Harvest by tapping a chunk of charcoal over the enclosure.
- Isopods: a tub with 5 to 8 cm of moist soil, a thick layer of leaf litter, a piece of cork bark and a calcium source (cuttlebone or crushed eggshell). Keep half damp and half drier, and feed vegetables and fish flakes weekly.
Through a Canadian winter, cultures near a cold exterior wall can slow right down. Keep them in a room that stays above about 18 °C; our winter guide covers humidity and heating for the whole build.
Signs your crew is struggling
- Mould persisting for more than two weeks on the same spot.
- No springtails visible when you lift a piece of bark or water the soil.
- Uneaten waste piling up on the surface.
- Soil that is bone dry on top and bottom (most crews need a damp layer).
The fix is usually more moisture in part of the enclosure, more leaf litter and a top-up from your backup culture. For a full routine, see how to maintain a bioactive terrarium.
FAQ
Do I need both springtails and isopods?
For most builds, yes. Springtails handle mould and fine waste in tight spaces, while isopods break down larger waste, leaf litter and wood. Together they cover far more than either one alone.
Will my animal eat the clean-up crew?
Some will, especially frogs and small lizards. That is fine as long as the crew can breed faster than it is eaten. Plenty of leaf litter and cork bark gives them hiding places, and a backup culture lets you top up.
Can isopods harm my reptile or tarantula?
Healthy, well-fed isopods are not a threat. Large, hungry species can nibble on moulting or sick animals, so use small soil-dwelling species with tarantulas and keep the crew fed in arid builds.
How long before I can add my animal?
Wait two to four weeks after adding the crew to a seeded, planted enclosure. This gives populations time to establish and lets you check that humidity and plants are stable.
Can a clean-up crew survive in a desert enclosure?
Yes, if you choose drought-tolerant species and keep a damp zone. Many keepers dampen one corner or bury a moist area under a flat stone or cork flat so the crew has somewhere to retreat.
Do I ever need to replace the crew?
A balanced crew is self-sustaining. You only need to top up if the population crashes after drying out, overheating or heavy predation.