Pet mouse diet: what to feed every day

What is the best food for pet mice?

The best food for pet mice is a complete, single-type nugget made for mice, or for rats and mice together. The RSPCA recommends nuggets because each one holds a balanced mix, so a mouse cannot eat only the tasty bits and leave the rest. The PDSA says the same: muesli-style mixes are sold for mice, but pellets give a more balanced diet.

Wild house mice eat seeds, grains, roots, plants, insects and even carrion, so pet mice are omnivores, not plant-eaters. A good nugget covers that mix in one bite. Pellets also help wear down a mouse's front teeth, which never stop growing, as the MSD Veterinary Manual points out.

What to look for on the label

• Labelled as a complete food for mice, or for rats and mice.
• A single type of nugget, not a colourful mix.
• No added sugar or molasses.
• Protein around 13 to 14%. The Crittery, a UK small-animal rescue, says some keepers keep adult mice at no more than 13% protein; Supreme's Science Selective Rat and Mouse food lists 14% protein, 4% fat and 4% fibre.
• Within its best-before date and stored somewhere cool and dry, as RSPCA Australia advises. Old food loses vitamins.

Science Selective Rat and Mouse food (Supreme Petfoods, UK) is a common example of this kind of food, with a feeding guide of 3 to 5 g a day for an adult mouse. In the US, check any mouse or rat-and-mouse block against the same list. Wood Green also names RatRations, a UK supplier, for a mouse-specific mix.

Nuggets or a mix: where the experts disagree

Most charities favour nuggets, but some experienced mouse keepers prefer a varied grain mix, and it is worth knowing why. The RSPCA, PDSA and RSPCA Australia all steer people towards nuggets, and RSPCA Australia says to avoid seed and grain mixes. Wood Green suggests a mouse-specific mix. The Crittery goes further and recommends a home-made mix built on a rat muesli with oats, barley and millets, because many shop foods contain low-value filler.

We follow the charities: nuggets as the base, because they stop picky eating and are hardest to get wrong. If you want the foraging fun of a mix, scatter a pinch of plain oats or millet as part of the daily amount. Crittery's tip works for both styles: wait until the bowl is empty before you refill it, so mice eat what they need and not just their favourites.

How much should a pet mouse eat a day?

An adult mouse eats about 3 to 5 g (0.1 to 0.2 oz) of food and drinks 3 to 5 ml (0.1 to 0.2 fl oz) of water a day, according to the MSD Veterinary Manual. Wood Green puts it at about 5 g per mouse, roughly a level teaspoon. That is tiny, so overfeeding is easy.

Use these as a starting point, then watch. Pet mice usually weigh 25 to 50 g (0.9 to 1.8 oz), says The Crittery, and show-type mice 60 g (2.1 oz) or more. If the bowl is always empty within hours and the mice are lean, add a little. If food is always left and they are getting round, cut back. The RSPCA warns that mice with unlimited food and too little to do become obese, and Crittery notes red mice put on weight especially easily.

What fresh food can pet mice have?

Pet mice can have small pieces of most vegetables and a little fruit, counted as part of their daily food, not extra. The RSPCA is clear on this, and PetMD keeps all extras, from grains to fruit and treats, to no more than 10% of the daily diet. For a mouse eating 4 g, that is a piece about the size of your little fingernail.

• Good everyday veg: carrot, broccoli, peas, sweetcorn (corn), curly kale and sweet potato, all on The Crittery's list.
• Fruit, now and then: apple without pips, banana, blueberries and papaya. RSPCA Australia keeps fruit for training rewards and special occasions.
• Go easy: watery foods such as cucumber and watermelon can cause diarrhoea, so give them sparingly.
• Take it out: PetMD says to remove fresh food after 10 hours so it does not go off in the nest.

Our full list of what mice can eat sorts every common food into yes, sometimes and no. You can also check single foods such as carrots, broccoli and apples.

Do pet mice need protein?

Yes, a little. Mice are omnivores, and Wood Green suggests a small amount of boiled egg or one or two fresh mealworms at a time. The Crittery adds scrambled egg, monkey nuts (peanuts in the shell) and a small amount of cheese, but warns against too much protein once mice are past the baby stage.

Cheese is a split point. Crittery lists it as an occasional protein, while RSPCA Australia says to avoid dairy and high-fat foods. We treat it as a rare, crumb-sized extra at most, and explain why in can mice eat cheese. Egg and mealworms are the easier choice.

What treats are healthy for pet mice?

The healthiest treats are plain, low in sugar and given in crumb-sized amounts. Wood Green's list:

• Cooked or raw plain pasta
• A small piece of boiled egg
• Cooked pulses (plain beans or lentils, never raw)
• Low-sugar cereal, under 5% sugar
• One or two fresh mealworms
• A small piece of plain dog biscuit to gnaw
• Millet spray, hung up to forage from
• Apple or other fruit tree wood to chew

The Crittery adds sunflower and pumpkin seeds, cooked soya beans and stale or toasted wholemeal bread. Seeds are fatty, so give one or two, not a handful. Wood Green warns against coloured chew sticks and mineral or salt blocks, which mice do not need. Hand-feeding treats is also the quickest way to win a mouse over, as our guide to taming a pet mouse explains.

Which foods are dangerous for mice?

Never give grapes, raisins or rhubarb: the RSPCA lists all three as poisonous to mice. The RSPCA also says lettuce can cause diarrhoea. PetMD adds garlic, onions, unripe tomatoes, raw beans, potatoes, chocolate, caffeine, alcohol, fruit seeds and stones, citrus, and sugary or fatty treats.

RSPCA Australia also asks owners to keep human snacks such as crackers, bread, processed cereals and sweets away from mice. Chocolate is covered in detail in can mice eat chocolate.

How do you give a pet mouse water?

Give fresh water every day, in a bottle, a bowl or both. The RSPCA prefers bottles with metal spouts, checked daily for leaks and blockages. Wood Green notes many mice prefer a bowl and that bottles often leak, while the MSD manual keeps bowls for emergencies because mice kick bedding into them.

We use a bottle as the main supply with a small, heavy bowl as a back-up, and check both morning and evening. Nesting pushed against a spout can stop it working, and a mouse cannot go long without water.

How to feed pet mice: a daily routine

1. Feed in the evening. PetMD suggests evening feeding, when mice wake up and start to forage.
2. Weigh or measure the nuggets. About a level teaspoon per mouse. Use a kitchen scale for the first week so your eye learns the amount.
3. Scatter most of it. The RSPCA and PDSA both suggest scattering food so mice forage as wild mice do. It also stops one mouse guarding the bowl.
4. Add the fresh piece. A fingernail-sized bit of veg per mouse, taken out of the daily amount.
5. Refresh water. Empty, rinse and refill the bottle or bowl, and press the spout to check it flows.
6. Clear yesterday's leftovers. Remove fresh food left from the day before and any wet or spoiled nuggets.

Hiding food in tubes, boxes and paper parcels turns dinner into the best part of their day. Ideas are in our pet mouse enrichment guide.

Is it normal for mice to eat their droppings?

Yes. Mice eat some of their own droppings to take in nutrients such as vitamin B12 and folic acid, says the RSPCA, and the MSD manual calls it normal. Do not try to stop it. What does need a vet is diarrhoea, weight loss or a mouse that stops eating; our pet mouse health guide lists the signs.

For the rest of their care, from cage to company, see our complete pet mouse care guide.