Porcellio scaber "Rust" is a colour morph of the common rough woodlouse showing warm reddish-brown to orange-brown colouration—the colour of weathered iron or autumn leaves. It's the same bulletproof species you might find under logs in your garden, just wearing a more attractive outfit. P. scaber has been a foundation species in the isopod hobby precisely because it tolerates nearly anything you throw at it. The Rust morph adds visual interest without sacrificing any of that hardiness, making it a sensible choice for beginners and a practical option for bioactive cleanup crews.
A Glimpse
-
Origin: Europe (captive-bred colour morph)
-
Scientific Name: Porcellio scaber "Rust"
-
Common Names: Rust Scaber, Rust Rough Woodlouse
-
Maintenance required: Low
-
Average Size: 15-18mm
-
Rarity: Uncommon morph of a very common species
-
Temperature: 15-29°C (59-84°F)
-
Ventilation: Medium to High
-
Humidity: 50-70% (with moisture gradient)
-
Favorite food: Leaf litter, decaying wood, vegetables
-
Supplements: Protein (fish flakes), calcium (cuttlebone)
Porcellio scaber "Rust": Introduction
Porcellio scaber—the common rough woodlouse—is native to Western Europe but has spread worldwide through human activity. You've almost certainly seen wild-type specimens: the grey, bumpy-backed woodlice found under rocks, logs, and plant pots across the UK. They're called "rough" woodlice because of the small tubercles covering their exoskeleton, giving them a textured appearance compared to smoother species.
The Rust morph displays a warm reddish-brown colouration ranging from subtle copper tones to deeper burnt orange-brown. Individual variation exists within the morph—some specimens lean more orange, others more brown, and the intensity varies between individuals. This variation adds visual interest to established colonies.
What makes P. scaber popular isn't complicated: they're nearly impossible to kill through normal husbandry mistakes. They tolerate a wide range of temperatures, handle both drier and more humid conditions, breed readily, and eat almost anything organic. For beginners learning the basics of isopod care, or for keepers who want a reliable cleanup crew without constant attention, P. scaber morphs deliver.
Porcellio scaber "Rust": Physical Traits and Characteristics
- Adults reach 15-18mm in length
- Oval-shaped body with characteristic rough, tuberculate texture
- Reddish-brown to orange-brown colouration (rust tones)
- Individual variation in colour intensity and pattern
- Juveniles may appear lighter, with colour deepening as they mature
- Cannot roll into a complete ball (unlike Armadillidium species)
- Seven pairs of legs
- Two obvious antennae
The rough texture distinguishes P. scaber from smooth-bodied species at a glance. The rust colouration shows well against dark substrates and provides reasonable visibility in bioactive setups without being as conspicuous as brighter orange morphs.
Behaviour
Porcellio scaber is an active, visible species once colony numbers build up.
Activity patterns: Primarily nocturnal in the wild, but captive specimens often show daytime activity, particularly when moving between moisture zones. Higher numbers mean more visible activity.
Movement: They migrate between moist and dry areas based on their hydration needs. Research has found they're actually more active in drier conditions and slower in humid air—so expect more movement in the drier zones of your enclosure.
Defence: They cannot roll into a ball like Armadillidium species. Instead, they rely on speed and their armoured exoskeleton. When disturbed, they'll scatter and seek cover.
Social behaviour: Gregarious. They aggregate under favourite hiding spots and show no territorial behaviour. Crowding doesn't cause problems—in fact, population density can positively affect growth rates.
Climbing: Capable climbers. Secure lids are sensible, though they're not determined escape artists.
Diet
P. scaber are unfussy feeders that consume a wide range of organic matter.
Primary foods:
- Leaf litter (oak, beech, and other hardwoods)
- Decaying wood (white-rotted wood preferred)
- Decomposing plant matter
Supplementary foods:
- Vegetables: carrots, courgette, squash, cucumber, sweet potato
- Occasional fruit (sparingly)
- Commercial isopod foods
Protein: Porcellio species have relatively high protein requirements. Offer protein sources once or twice weekly:
- Fish flakes or pellets
- Freeze-dried shrimp or minnows
- Dried insects
Important note: Underfed P. scaber (particularly protein-deficient colonies) have been known to nibble on soft-skinned reptiles. Provide adequate protein to prevent this.
Calcium: Provide cuttlebone, crushed limestone, or oyster shell. They need calcium for exoskeleton development, particularly females producing young.
Feeding approach: Keep leaf litter and decaying wood available at all times—this forms the bulk of their diet. Supplement with vegetables and protein regularly. They're coprophagous (consume their own droppings) which helps them retain gut bacteria and extract additional nutrients.
Porcellio scaber "Rust": Breeding
P. scaber breeds readily with no special requirements.
Breeding basics:
- Very prolific once established
- Fast reproduction in good conditions
- Sub-adults can begin breeding before reaching full size
- Females carry eggs in a fluid-filled brood pouch (marsupium)
- Development time approximately 6 months from birth to maturity
Environmental factors: Warmer temperatures (mid-20s Celsius) produce more active colonies with faster breeding. They'll still breed at cooler temperatures, just more slowly.
Brood size: Females produce multiple broods throughout their lifespan. Expect population growth to accelerate once the colony establishes.
Mancae (babies): Newly released young are more vulnerable to desiccation than adults. Maintain a good moisture gradient so mancae can access humid areas during their vulnerable early stages.
Lifespan: Adults typically live 2-3 years under good conditions.
Porcellio scaber "Rust": Habitat Setup
Simple requirements make this species ideal for beginners.
Enclosure: A 6-quart container suits a starter culture. For established colonies, 15+ quart containers or 10+ gallon terrariums work well. Plastic storage boxes with gasket seals are practical. Provide adequate ventilation—P. scaber appreciates good airflow.
Substrate: Use a moisture-retaining substrate that provides food and burrowing opportunities:
- Organic topsoil as base (pesticide-free)
- Sphagnum peat moss mixed in for moisture retention
- Decaying hardwood pieces
- Leaf litter layered on top
- Crushed limestone or calcium powder mixed into substrate
Depth of 5-8cm allows burrowing. The substrate itself becomes part of their diet as it decomposes.
Humidity: 50-70% with a moisture gradient:
- Keep approximately one-third of the enclosure moist (damp sphagnum moss works well)
- Leave the remainder drier with good ventilation
- Allow isopods to choose their preferred moisture level
- Cork bark placed over moist areas helps retain humidity
P. scaber tolerates drier conditions better than many species, making them suitable for enclosures housing animals that prefer lower humidity. However, they still need access to moisture—they cannot survive truly arid conditions.
Ventilation: Medium to high. Good airflow prevents stagnation and seems to suit this species. They're more active in well-ventilated setups than in stuffy, overly humid enclosures.
Temperature: 15-29°C (59-84°F). Room temperature in UK homes works perfectly. Mid-20s Celsius produces the most active, productive colonies. They tolerate significant temperature variation without problems—night drops into the mid-teens cause no issues.
Décor:
- Cork bark pieces (on both moist and dry sides)
- Leaf litter (the more the better)
- Decaying wood pieces
- Egg carton sections work as hides if aesthetics don't matter
Bioactive Use
P. scaber makes an excellent bioactive cleanup crew for a wide range of setups.
Ideal applications:
- Temperate vivariums
- Tropical setups (they adapt)
- Semi-arid enclosures
- Reptile and amphibian bioactive systems
- General terrarium cleanup
Strengths:
- Tolerates wide humidity and temperature ranges
- Fast breeding maintains population under predation
- Efficient decomposers
- Active and visible
- Handles conditions that stress more demanding species
Considerations:
- High protein requirements—underfed colonies may nibble on inhabitants
- Medium size means larger predators will eat them (usually fine, but protein-feed the colony)
- May nibble soft plants, particularly if underfed
- Visible colouration may attract predator attention (can be positive or negative depending on your goals)
Good pairings: Works with most reptiles and amphibians that appreciate bioactive setups. Their tolerance for drier conditions makes them more versatile than humidity-dependent species.
Tank Mates
Compatible with most peaceful invertebrates and appropriate reptiles/amphibians.
Compatible:
- Other isopod species (if space allows)
- Springtails
- Small millipedes
- Snails
As cleanup crew for:
- Leopard geckos
- Bearded dragons
- Corn snakes
- Ball pythons
- Crested geckos
- Dart frogs
- Most reptile and amphibian bioactive setups
Note: They breed fast enough to sustain populations even when inhabitants eat some. Larger predators will treat them as food—this is usually acceptable and even beneficial, providing enrichment and supplementary nutrition.
Suitability
Porcellio scaber "Rust" suits a wide range of keepers and applications.
Good choice for:
- Complete beginners learning isopod husbandry
- Bioactive setup cleanup crews
- Keepers wanting low-maintenance colonies
- Those wanting attractive isopods at reasonable prices
- UK keepers (tolerates our climate naturally)
- Anyone who's killed more demanding species and wants something forgiving
Less suited for:
- Keepers specifically wanting rare or expensive species
- Those wanting isopods that roll into balls (Armadillidium does that, not Porcellio)
- Truly arid setups with no moisture access
Care level: Very easy. This is the species recommended for beginners because it tolerates the mistakes beginners make. Temperature swings, humidity fluctuations, missed feedings—P. scaber handles these better than most species. If you can't keep these alive, the problem is likely fundamental rather than species-specific.
Value: At £12.50 for 10, this represents reasonable value for a colour morph. Wild-type P. scaber can be collected free from most UK gardens, so you're paying for the rust colouration. Given their breeding rate, your initial purchase should expand into a substantial colony within months, making the per-isopod cost negligible long-term.
Other morphs available: P. scaber comes in numerous colour morphs:
- Wild type (grey)
- Orange
- Lava (orange/red on grey-black base)
- Dalmatian (spotted)
- Ghost (reduced pigmentation)
- Calico
- White Out
What to expect: Expect hardy, active isopods that get on with things without constant attention. Expect fast breeding once established. Expect them to survive mistakes that would kill fussier species. The rust colouration provides visual interest beyond wild-type grey, and individual variation means colonies develop their own character over time. They won't win awards for rarity, but they'll still be alive and thriving when more demanding species have failed. Sometimes that reliability is exactly what you need.
