Porcellio ornatus "High Yellow" is a Spanish species prized for its striking appearance—grey exoskeleton marked with bright yellow colouration that gives the morph its name. Reaching around 2.5cm, they're larger than many commonly kept isopods and display active, confident behaviour that makes them enjoyable to watch. Native to Spain's drier Mediterranean climate, they prefer lower humidity and good ventilation compared to tropical species. The High Yellow morph is a naturally occurring colour form rather than a captive-bred designer variety, giving it appeal among collectors who appreciate wild-type genetics.
A Glimpse
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Origin: Spain
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Scientific Name: Porcellio ornatus "High Yellow"
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Maintenance required: Medium
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Average Size: 2-2.5 cm
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Rarity: Rare
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Lifespan: 2-3 years
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Temperature: 20-26°C (68-79°F)
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Ventilation: High
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Humidity: 40-60% (low to moderate, drier than most)
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Favorite food: Leaf litter, vegetables, fruits, protein sources
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Supplements: Cuttlefish bone, crushed oyster shell, eggshells
Porcellio ornatus High Yellow: Introduction
Porcellio ornatus originates from Spain's Mediterranean regions, where the climate is characterised by warm, dry conditions with distinct wet and dry seasons. This heritage shapes their care requirements—they prefer drier, well-ventilated conditions that would stress humidity-loving species.
The "High Yellow" designation refers to the intensity of yellow colouration on their grey bodies. This is a natural morph found in wild populations, not a selectively bred variant. Several ornatus morphs exist, including Nord (grey with white spots), Yellow Dot/South (grey with yellow spots at the rear), and Chocolate High Yellow (brown instead of grey base). The High Yellow displays prominent yellow markings across the body against the grey base.
Their larger size and active nature make them genuinely watchable. Unlike shy species that hide constantly, ornatus move about openly, exploring surfaces and climbing on bark and décor. This extroverted behaviour, combined with their size and colouration, makes them satisfying display animals.
They're rated as intermediate difficulty—not beginners' first species, but manageable for keepers with some experience. Their preference for drier conditions runs counter to typical isopod advice, which can trip up those accustomed to humidity-loving species.
Porcellio ornatus High Yellow: Physical Traits and Characteristics
- Adults reach 2-2.5 cm—larger than many commonly kept species
- Grey base exoskeleton with prominent yellow markings
- Yellow colouration intensity varies between individuals
- Sturdy, well-armoured body
- Cannot fully conglobate (roll into a complete ball)
- Segmented body with visible plating
- Active, slow-moving gait
- Antennae used for environmental sensing
Their size makes them easy to observe and photograph. The yellow against grey creates genuine visual contrast that stands out in enclosures.
Behaviour
Porcellio ornatus High Yellow display confident, active behaviour.
Activity patterns: Unlike many isopods that hide from light, ornatus are not particularly shy. They'll crawl about on surfaces even with ambient lighting, making them more visible than photophobic species. They explore actively, moving across substrate, climbing bark, and investigating their environment.
Movement style: Slow-moving compared to quick species like P. laevis. They amble rather than dart, which makes observation easier and gives them a more deliberate appearance.
Temperament: Extroverted for isopods. They don't retreat immediately when disturbed and seem comfortable being visible. This personality makes them enjoyable display animals.
Climbing: Active climbers that will explore vertical surfaces, bark, and elevated décor. Secure lids prevent escapes.
Colony behaviour: Social species that do well in groups. They form loose colonies and interact with each other without notable aggression.
Environmental preferences: They move between drier and damper areas of enclosures based on their needs, self-regulating their moisture exposure.
Diet
Porcellio ornatus High Yellow have hearty appetites matching their active nature and larger size.
Primary foods:
- Leaf litter (staple food source)
- Decaying wood
- Rotting plant matter
- Bark
Vegetables and fruits:
- Carrots
- Potato
- Courgette
- Sweet potato
- Apple
- Various fruit and vegetable cuttings
Protein sources:
- Fish food flakes
- Dried shrimp
- Meat scraps (small amounts)
- Invertebrate moults (they'll consume shed skins)
Calcium: Higher calcium needs than some species. Provide cuttlefish bone, crushed oyster shell, eggshells, or calcium powder constantly. Adequate calcium supports healthy moulting and breeding.
Feeding approach: Their active nature means they burn through food. Keep them well-fed with varied diet including protein and calcium-rich options. They're not picky—most organic matter gets accepted. Remove uneaten fresh foods before they spoil.
Porcellio ornatus High Yellow: Breeding
Ornatus breed at a moderate rate with proper care.
Breeding rate: Moderate. Not explosive breeders, but colonies grow steadily when conditions are right. Sub-adults begin breeding before reaching full size if well-fed.
Brood characteristics: Medium to large brood sizes when nutrition is good. Healthy females produce decent numbers of offspring.
Breeding requirements:
- Appropriate drier conditions (40-60% humidity)
- Stable temperatures within preferred range (20-26°C)
- High protein and calcium availability
- Good ventilation
- Moisture gradient available
Tips for success: Nutrition matters. Well-fed colonies with adequate protein and calcium breed more prolifically and produce healthier offspring. Don't skimp on supplements if you want colony growth.
Maintaining the morph: Keep separate from other ornatus morphs to maintain the High Yellow colouration in offspring.
Porcellio ornatus High Yellow: Other Morphs
Several ornatus morphs exist for those interested in the species:
Porcellio ornatus Nord: Grey shells with white spotting and white skirts. Different appearance from the yellow variants.
Porcellio ornatus Yellow Dot (South): Dark grey body with yellow dots concentrated on the rear segments. More subtle yellow than High Yellow.
Porcellio ornatus Chocolate High Yellow: Same yellow markings as High Yellow but on a chocolate brown base instead of grey. Attractive variant for those wanting something different.
Each morph breeds true when kept separately, allowing collectors to maintain distinct lines.
Porcellio ornatus High Yellow: Habitat Setup
Their Spanish Mediterranean origins dictate drier, well-ventilated conditions.
Enclosure: Glass terrariums or well-ventilated plastic containers work well. Good ventilation is a priority—they need airflow more than humidity retention. Secure lids prevent climbing escapes.
Substrate: Use substrate appropriate for drier conditions:
- Organic topsoil as a base (pesticide-free)
- Sphagnum peat moss mixed in sparingly
- Sand mixed in for drainage
- Crushed limestone or calcium powder throughout
- Leaf litter layered on top
- Decaying wood pieces
Substrate depth of 8-10cm (3-4 inches) allows burrowing. Keep substrate just moist, not wet.
Humidity: Lower than most isopod species—40-60%:
- Keep approximately ¼ of enclosure as a moist area
- Leave remaining ¾ drier
- Mist the wet side only to create moisture gradient
- Add moss to the wet side for moisture retention
- Let them move between zones as needed
Excess humidity can affect their health and breeding. They're adapted to drier conditions than tropical species.
Ventilation: High ventilation—this is a key requirement. Good airflow prevents humidity buildup and mimics their natural arid habitat. Enclosures with ventilation outlets or containers with mesh-covered openings work best. Don't restrict airflow trying to maintain high humidity—they don't need it.
Temperature: 20-26°C (68-79°F). Moderate temperatures suit them. Avoid extremes—they don't tolerate very hot or very cold conditions well. Room temperature in UK homes works for most of the year.
Décor and hides:
- Cork bark pieces and tubes
- Coconut shell halves
- Lotus pods
- Egg carton sections
- Various mosses (sheet and pillow types)
- Rotting wood pieces
- Multiple hiding spots distributed throughout
Varied textures and hide options create a more interesting environment that encourages natural behaviour.
Bioactive Use
Porcellio ornatus High Yellow suit bioactive setups matching their drier requirements.
Good applications:
- Mediterranean-style vivariums
- Arid to semi-arid bioactive setups
- Enclosures for reptiles preferring drier conditions
- Display terrariums where visible, active isopods are wanted
Strengths:
- Active, visible behaviour
- Attractive colouration adds interest
- Larger size makes them easy to observe
- Handle drier conditions than humidity-loving species
Considerations:
- Need good ventilation—not suited to humid, enclosed setups
- Prefer drier conditions than many bioactive systems provide
- Intermediate care level means they're not as forgiving as hardy species
Less suited for:
- High-humidity tropical setups
- Poorly ventilated enclosures
- Beginners with no isopod experience
Suitability
Porcellio ornatus High Yellow suit keepers wanting attractive, active isopods from drier habitats.
Good choice for:
- Keepers with basic isopod experience ready for something more interesting
- Those maintaining drier bioactive setups
- Collectors interested in Spanish Porcellio species
- Anyone wanting visible, active display isopods
- Keepers who find shy, hiding species frustrating
Less suited for:
- Complete beginners (start with hardier species)
- High-humidity tropical setups
- Those who can't provide good ventilation
- Keepers expecting bulletproof, mistake-tolerant species
Care level: Intermediate difficulty. They're not demanding once you understand their drier preferences, but keepers accustomed to humidity-loving species may need to adjust their approach. The ventilation requirements are the opposite of what Cubaris keepers are used to. Those with experience keeping Mediterranean species will find them straightforward.
Value: At £25 for 10, they offer good value for an attractive, naturally occurring morph with interesting behaviour. Their larger size and confident personality make them more engaging than smaller, shyer species. They're visually interesting without the premium pricing of rare Cubaris.
What to expect: Expect active, visible isopods that actually do something worth watching. Expect attractive colouration that photographs well. Expect moderate breeding that builds colonies over time. Don't expect them to thrive in humid, poorly ventilated setups—their needs are different from tropical species. Give them the drier, airier conditions they prefer, and they'll reward you with healthy, active colonies.
