Yellow Fellow Isopods (Armadillidium Klugii)

Yellow Fellow Isopods (Armadillidium klugii 'Yellow Fellow') are a selectively line-bred morph of the popular Clown isopod, developed by JW Invertebrates in the UK. This isolated line has been bred to express enhanced yellow colouration across the carapace, giving them a distinctive appearance compared to the standard Montenegro or Dubrovnik varieties. While they share the same care requirements as other klugii, their increased yellow expression makes them a sought-after addition for collectors looking for something a bit different.

A Glimpse

• Origin: UK (Line bred from Armadillidium klugii)
• Scientific Name: Armadillidium klugii 'Yellow Fellow'
• Difficulty Level: Low to Medium
• Size: Up to 1.8 cm
• Rarity: Rare
• Temperature: 64℉ to 82℉ (18°C to 28°C)
• Humidity: 50% to 70% with moisture gradient
• Favourite Foods: Leaf litter, decaying wood, vegetables, fish food
• Supplements: Cuttlebone, calcium powder

Yellow Fellow Isopods: An Overview

Yellow Fellow isopods are a UK-produced line bred variant of Armadillidium klugii, selected specifically for their increased yellow spotting and reduced red skirt colouration compared to standard Clown morphs. Created by JW Invertebrates through careful selective breeding, this isolated line breeds true for the enhanced yellow expression.

Like all klugii, they retain the characteristic hard calcified carapace and the signature spotted pattern that earned the species the "Clown" nickname. However, keepers should note that individual variation still exists within the line, and some specimens may show more or less yellow than others. This is normal for any line bred morph and part of what makes each isopod unique.

These isopods share the typical klugii temperament - they can be somewhat shy and prefer to burrow rather than climb. They are more active during evening hours and may take some time to settle into a new enclosure. Once established, they are reasonably prolific breeders, though patience is required during the initial culture phase.

Yellow Fellow Isopods: Characteristics

• Line bred in the UK by JW Invertebrates for enhanced yellow expression.
• Features prominent yellow spots across the carapace with a darker base colour.
• Some individuals may retain subtle red/orange edging, though this is reduced compared to standard klugii.
• Hard, calcified exoskeleton typical of Armadillidium species.
• Capable of rolling into a tight ball when disturbed as a defensive mechanism.
• Prefer to burrow rather than climb.
• Can be slow to establish but are prolific once settled.
• Nocturnal, most active during evening hours.

Yellow Fellow Isopods: Basic Care

Yellow Fellow isopods require the same care as other Armadillidium klugii varieties. Here are the key points to help them thrive:

• Use a well-ventilated enclosure. Good airflow is important for this species.
• Maintain a moisture gradient with approximately one-third of the enclosure kept damp and two-thirds dry.
• Avoid overly humid tropical setups. These isopods can struggle with excess moisture.
• Provide a substrate depth of 2-3 inches to allow for burrowing.
• Cork bark, egg cartons, and leaf litter provide essential hiding spots.
• Temperature should be kept between 64°F and 82°F. Slightly warmer temperatures can encourage breeding.
• Avoid placing the enclosure in direct sunlight.
• New cultures may be slow to get going. Patience is needed during the establishment phase.

Yellow Fellow Isopods: Substrate

The substrate setup is important for klugii varieties. Unlike tropical species, Yellow Fellow isopods do not tolerate consistently wet conditions well.

A suitable base consists of sphagnum moss, peat moss, and sand mixed together. Avoid pure coco coir setups as this can retain too much moisture for this species. The wet corner should use a moisture-retaining mix like ABG substrate, while the majority of the enclosure remains drier.

Add plenty of leaf litter (oak, beech, or magnolia work well) and pieces of decaying softwood. These serve as both food and hiding places. Cork bark flats provide excellent shelter and help the isopods feel secure.

Supplement the substrate with calcium sources such as crushed cuttlebone or oyster shell. This supports healthy moulting and maintains their calcified exoskeleton.

Yellow Fellow Isopods: Diet

Yellow Fellow isopods are detritivores and will consume most standard isopod foods:

• Primary diet: Decaying leaf litter and softwood should always be available in abundance.
• Vegetables: Carrot, sweet potato, squash, and other kitchen scraps. Keep portions small and offer drier options to prevent mould.
• Protein: Dried shrimp, fish food flakes, or commercial isopod protein supplements. Offer 1-2 times per week.
• Calcium: Essential for their hard carapace. Provide cuttlebone, crushed eggshells, or calcium powder.

Remove any uneaten fresh food promptly to prevent mould growth, as mould can be harmful to the colony.

A Note on Line Bred Morphs

As with any selectively bred line, Yellow Fellow isopods should ideally be kept separate from other klugii varieties to maintain the line integrity. Mixing with standard Clown isopods or other klugii morphs will result in offspring that may lose the enhanced yellow expression over subsequent generations.