American Giant Millipedes -- Perfect Snail Terrarium Pals

American Giant Millipedes (Narceus americanus)
Millipedes make excellent companions for snail terrariums. Peaceful and slow-moving, they help break down decaying leaves and organic matter, supporting a clean, balanced habitat. They thrive in the same humid, bioactive environments as snails and are great for naturalistic displays and educational setups.

In ideal conditions (deep moist substrate, leaf litter, stable humidity), some large females can reach close to 5 inches, though 4 inches is more common.

They grow slowly and may take 1.5–2 years to reach full size, and they can live 5–7+ years in captivity.

• Length: Fully grown Adult Length is 3 to 4.5 inches (7.5–11.5 cm)

• Diameter: About the width of a pencil when fully grown

• Temperament: Calm and non-aggressive

• Role: Natural cleanup crew

• Habitat: Moist substrate with leaf litter and hiding spots

• Compatibility: Safe with land snails

Millipede Care Mini-Guide (Snail-Safe)
Compatibility

Millipedes are peaceful and safe to keep with land snails. They share similar humidity and temperature needs and won’t harm snails or eggs.

Habitat

• Enclosure: Bioactive terrarium with good ventilation

• Substrate: 2–4 inches of moist coco coir mixed with leaf litter and decayed wood

• Hides: Cork bark, moss, and leaf cover for burrowing

Humidity & Temperature

• Humidity: 70–90% (light misting as needed)

• Temperature: 65–78°F

• Avoid direct heat sources and dry conditions

Diet

• Decaying leaves, rotting wood, and leaf litter (staples)

• Supplement with cucumber, zucchini, squash, or melon rinds

• Remove uneaten fresh food within 24 hours

Calcium

• Provide cuttlebone or calcium powder to support exoskeleton health

Care Tips

• Handle gently and infrequently

• Keep substrate consistently moist, not soggy

• Spot-clean and refresh leaf litter regularly

Good to Know

Millipedes are natural decomposers and help keep snail habitats clean and balanced.