What Do Roly Polies (Isopods) Eat?

Roly polies have one of the best jobs in nature: eating the stuff nobody else wants. Dead leaves, rotting wood, decaying plants... to an isopod, that's a five-star buffet.

Whether you've got a few backyard roly polies in a jar or a bin full of designer isopods, here's what they actually eat, and how to keep your colony healthy and breeding.

What Do Roly Polies Eat in the Wild?

Roly polies (isopods) are detritivores, which means they eat decaying organic matter. In the wild, that's mostly:

  • Fallen, decomposing leaves
  • Rotting wood and bark
  • Decaying plant material
  • The occasional dead insect or other bit of protein

That's why they're such good clean-up crews in bioactive enclosures. They turn waste and dead plant matter back into soil.

What to Feed Pet Isopods

1. Leaf Litter (the main course)

Leaf litter should make up a major part of your isopods' diet, and it doubles as cover and hiding spots. Oak and magnolia break down slowly and last a long time; softer leaves like maple break down faster. Mixing a few types works great. Don't be stingy with the leaves!

Use pesticide-free leaves from hardwood trees, and skip strongly aromatic or resinous ones. Our Leaves & Wood guide covers which leaves we use, which we avoid (like black walnut), and how we prepare them. Don't want to collect your own? Shop our leaf litter.

2. Decaying Hardwood

Soft, rotting hardwood is a staple food for many species, especially Cubaris. It also gives them places to hide and breed. Stick with pesticide-free hardwoods and avoid treated, painted or resinous wood. (More in our Leaves & Wood guide.)

3. Calcium (don't skip this one)

Isopods are crustaceans, and crustaceans need calcium to build and rebuild their exoskeletons, especially when they molt. Keep a calcium source available at all times. Common options include:

  • Calcium carbonate powder
  • Crushed oyster shell
  • Cuttlebone
  • Limestone
  • Crushed eggshells

Some species are picky. Our Milkbacks and Dairy Cows, for example, prefer powdered eggshell and cuttlebone over limestone powder. Shop our calcium carbonate powder and other habitat supplies.

4. Protein (a little goes a long way)

Many isopods benefit from a small amount of protein, especially fast breeders. Good options include dried shrimp, fish flakes and freeze-dried minnows. Protein-hungry species like scabers and laevis do well with protein about twice a week.

Pro tip: scaber isopods (like Lavas and Dalmatians) may start snacking on each other if they don't get enough protein. Keep the protein coming!

5. Veggies and Treats

Isopods enjoy fresh and dried vegetables like carrot, cucumber, zucchini, squash, sweet potato and pumpkin. Different colonies have different favorites, so experiment. (Science teachers love using Dairy Cows for Halloween pumpkin decomposition experiments, and the isopods are big fans too.)

Want to boost color? Foods high in carotenoids, like carrot, pumpkin, corn and sweet peppers, are popular with keepers of orange and red morphs.

Isopod Feeding Do's and Don'ts

  • Do keep leaf litter and wood available at all times.
  • Do always provide a calcium source.
  • Do start small and remove uneaten supplemental food before it spoils or molds.
  • Don't overfeed. More food isn't always better, and leftovers can attract mold, mites and fungus gnats.
  • Don't use leaves, wood or produce that may have been treated with pesticides.
  • Do use a small dish for powders and treats so they stay off the substrate. Our 3D printed feeding dishes work great.

Want more on what goes wrong when feeding goes sideways? See Why Isopod Colonies Crash.

What About Springtails?

Springtails, the tiny clean-up crew that often lives alongside isopods, eat mold, fungi and decaying matter in the enclosure. For dedicated springtail cultures, we use our own Springtail Food.

Isopod Food FAQ

What do roly polies eat? Mainly decaying leaves and wood, plus calcium, a bit of protein, and vegetables as treats.

Do isopods need calcium? Yes. As crustaceans, they need it to molt and build their exoskeleton.

How often should I feed isopods? Keep leaf litter, wood and calcium available at all times. Offer supplemental foods in small amounts and watch how quickly your colony eats them.

Can isopods eat fruit? Yes, in small amounts. Just remove leftovers before they mold.

Ready to start your own colony? Check out our fast-breeding isopods.

Thanks for rolling with us!

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