Pet Mice Food – Feeding your Pet Mouse

Keeping a pet mouse well fed is usually less about “finding the perfect mix” and more about avoiding quiet, common problems: selective eating, weight gain, and missing nutrients that only show up later as poor coat condition, dental issues, or repeated illness. A good diet also changes how a mouse uses its enclosure—more chewing, more foraging, and steadier energy through the night. A reliable starting point is simple: a formulated mouse pellet or cube as the staple, small amounts of fresh foods for variety, and treats kept genuinely occasional. The details below are geared to what’s commonly available in Australia and to the way mice actually eat—picking favourites first, and leaving the rest behind.^{1, 2}

What a pet mouse needs from food

Pet mice are omnivores. They do best on a diet that consistently provides enough protein, essential vitamins and minerals, and safe fibre sources—without relying on “bits” they can pick around.²

In practice, that means a formulated mouse pellet or cube should make up most of the diet, with fresh vegetables and tiny amounts of fruit offered for variety and interest, not as the foundation.^{2, 3}

Why pellets (or cubes) matter

Formulated mouse foods are designed to be “complete”, so each mouthful is broadly similar. This is the main advantage over seed mixes: mice commonly cherry-pick the fattiest, tastiest items and leave the rest, which can lead to obesity and dietary imbalance over time.²

Chewing is a nutritional issue, too

Mice have continuously growing incisors and need regular opportunities to gnaw. A diet and setup that encourages chewing helps prevent dental overgrowth and supports normal behaviour. Pellets/cubes assist, but chewing enrichment (safe wood, chew items) also matters.⁴

Best staple foods: what to buy

Choose a good-quality pellet or cube formulated specifically for mice (or mice/rats), stored properly and used before its best-before date. Avoid using rabbit or guinea pig pellets as a stand-in—they’re not balanced for mice.⁴

What to look for on the label

• Formulated pellets/cubes as the staple, rather than a muesli/seed mix.²
• Protein and fat in a sensible range. As a guide, RSPCA Victoria notes pellets/cubes should have at least 16% protein and around 4–5% fat; the RSPCA knowledgebase also notes a typical target of about 14–16% protein and ~5% fat for adult mice, with higher protein needs for breeding animals.^{1, 2}

Seed mixes: where they fit (and where they don’t)

Seed/grain mixes are often marketed for mice, but they’re easy to overfeed and easy for mice to “sort”. If you use them at all, treat them as occasional enrichment rather than a staple diet.^{1, 2}

Fresh foods: how to supplement safely

Fresh foods add variety and can encourage natural foraging. Keep portions small and remove leftovers promptly so they don’t spoil in bedding. Fresh foods should stay within roughly 10% of the overall diet.^{2, 3}

Good everyday choices

Offer small amounts of vegetables more often than fruit. Dark leafy greens and non-starchy vegetables are common go-tos.²

• Vegetables/greens (small amounts): bok choy and other Asian greens, parsley, kale, beet greens, broccoli, green beans, carrot, zucchini.²
• Fruit (treat-sized amounts): apple, berries, kiwi (infrequently).²

Food hygiene basics

• Only offer fresh food that’s clean and free from mould or spoilage.¹
• Introduce new foods gradually to reduce the risk of gut upset.¹
• Serve at room temperature and remove uneaten fresh food the same day.

Treats and snacks: keep them small, keep them rare

Treats are best used as enrichment—something to search for, nibble, and carry—rather than a daily extra meal. A practical ceiling is under 10% of total intake (and many mice do better with less).^{2, 3}

Treat ideas that suit mice

• Small amounts of cereals, grains, seeds, bread, cooked pasta or rice—only occasionally.¹
• Seeds, nuts, pasta or a wholegrain cracker as infrequent treats (about 1–2 times a week).³

Foods best avoided

Some “people foods” are risky for many pets and are best kept out of a mouse’s enclosure altogether—especially anything sugary, salty, sticky, or strongly seasoned. The RSPCA also advises avoiding foods considered harmful for cats and dogs, listing examples such as chocolate, grapes/raisins, avocado, garlic, onion, coffee, tea and alcohol.²

• Chocolate and caffeine products⁶
• Grapes and raisins⁶
• Onion, garlic and related allium vegetables^{6, 7}
• Alcohol⁶
• Sticky foods that can lodge in the mouth (a choking risk)²

Water: simple, constant, checked daily

Provide fresh, clean water at all times. Water bottles are often cleaner than bowls because bowls can quickly fill with bedding and droppings; bottles also need checking to ensure they’re not blocked or leaking. Having more than one bottle is a sensible backup.²

Feeding through life stages

Mice don’t eat like clockwork. They’re largely nocturnal, with most food and water intake happening overnight, so it’s normal to see more activity at dusk and through the night.²

Young, growing mice

Growing mice need a reliable staple diet that meets their nutritional requirements. If you’re unsure whether a “mouse” food is suitable for youngsters, check the label and confirm with a vet—especially if the mouse is still very small or newly weaned.³

Adult mice

For most adults, pellets/cubes remain the base diet, with small amounts of vegetables and very small, infrequent treats. This pattern helps limit selective feeding and weight gain.^{2, 3}

Pregnant, breeding, or unwell mice

Breeding animals often require higher protein levels than typical adults. For any pregnant or unwell mouse, it’s worth speaking with an experienced vet early—small animals can deteriorate quickly, and appetite changes can be an early warning sign rather than a minor quirk.^{2, 3}

Common feeding mistakes (and what to do instead)

Relying on a seed mix as the main diet

Seed mixes encourage “best bits” eating. Over time, that can mean excess fat intake and missed micronutrients.^{1, 2}

Do instead: make pellets/cubes the staple, and use seeds as occasional enrichment.²

Too many treats “because they’re small”

With a mouse, a fingernail-sized portion can be a meaningful amount of food. Treat creep is easy.³

Do instead: keep treats under 10% of the diet, and offer them a couple of times a week at most.^{2, 3}

Not removing fresh leftovers

Fresh food spoils quickly in warm, damp bedding, and mice will still investigate it. That’s how stomach upsets start.

Do instead: offer small portions, remove leftovers the same day, and keep water sources clean.²

Forgetting the “gnaw” requirement

Diet is part nutrition and part behaviour. A mouse that can’t chew enough is set up for problems.⁴

Do instead: provide a proper staple diet plus safe chew opportunities, and watch for signs of dental trouble (drooling, dropping food, weight loss).⁴

References

1. RSPCA Victoria — Caring for pet mice and rats
2. RSPCA Knowledgebase — What should I feed my mice? (Updated 15 August 2024)
3. VCA Animal Hospitals — Feeding Rodents
4. RSPCA Knowledgebase — How should I care for my mice?
5. RSPCA Knowledgebase — What should I feed my rats?
6. ASPCA — People Foods to Avoid Feeding Your Pets
7. Morris Animal Foundation — Harmful/Toxic Foods for Dogs and Cats
8. American Humane Society — Pets & Poisons