Guinea Pig Diet Guide: Complete Health and Nutrition for Cavies

Discover what Guinea pigs eat so you can offer the most suitable diet for your pet's happiness and vitality.

Published April 2, 2023
Guinea pig eating zucchini

Guinea pigs are herbivores, so their diet should consist mostly of hay and grass. They also eat vegetables and fruits, but you should only give these in small amounts because they can cause stomach upset if your cavy eats too much. Guinea pigs need a constant supply of fresh food and water to stay healthy. If there's not enough available, they'll eat less and become malnourished. However, this is a balancing act, as they will overeat if provided the opportunity.

What Do Guinea Pigs Eat?

Guinea pig eating hay

Like most other animals, your Guinea pig needs variety in their diet. Their diet should consist of the following:

  • Commercial food: Food made specifically for Guinea pigs are developed with their specific needs in mind. Feed ⅛ cup of pellets daily. Search for commercial pellets that have been fortified with vitamin C.
  • Hay: High-quality hay, such as Timothy hay, is a crucial part of your Guinea pig's diet and it should be offered all day, every day. Offer a clump of hay about the size of their body. Without hay, your Guinea pig will not properly digest their food, which could result in severe gastrointestinal upset. Hay should be changed daily, as it tends to become moldy quickly if left out too long. If you have more than one Guinea pig, you may need to purchase additional hay to keep enough for everyone available at all times.
  • Fruits and Vegetables: Fruits and veggies offer additional variety and fill any nutritional gaps your pet may have, but only offer these as treats, and not the main part of their diet.
  • Other Treats: It's OK to give your cavy other Guinea pig treats, either in the form of commercial treat products or appropriate fruits, like a little bit of melon, should never comprise over 10% of your pet's diet.
Need to Know

The three best types of hay for Guinea pigs are Timothy, orchard, and oat hay.

Guinea Pigs Need to Wear Down Their Teeth

To stay healthy, your cavy needs to chew on enough roughage to ensure that their teeth don't overgrow. Guinea pig teeth never stop growing, and without the appropriate materials to gnaw on, their teeth can actually get too large and damage their mouths. Chewing on hay throughout the day also helps them wear their teeth down. Blocks of untreated wood or Guinea pig-safe chew toys are ideal to help them keep their teeth in check.

Offering a Fruit Snack

In addition to your guinea pig's commercial diet, they can eat the following fruits as a snack:

  • Apples
  • Strawberries
  • Melon pieces
  • Orange slices
  • Banana pieces
  • Watermelon

With fruits like apples or any that have seeds, you must remove the core and all the seeds prior to feeding. Fruits are high in sugar content, and your Guinea pig only needs a little bit to be happy. Keep slices or pieces of fruit small, and limit your cavy to no more than three servings of appropriately sized small chunks or slices of fruits each week.

Vegetables are Great Snacks

Guinea pigs do very well with vegetables, and these are usually healthier snacks for your cavy. Vegetables don't contain as much sugar as fruits, and your pet needs these in their diet to stay healthy. Give these leafy greens and vegetables that are high in vitamin daily.

  • Collard greens
  • Swiss Chard
  • Kale
  • Romain lettuce
  • Cilantro
  • Parsley
  • Cucumbers cuts
  • Beetroot
  • Broccoli
  • Brussels sprouts
  • Turnips

Other vegetable treats are healthy for your cavy, but limit these to once-a-week treats:

  • Carrots
  • Tomatoes
  • Bell Pepper slices - green are best
  • Celery chunks
  • Zucchini slices

Variety is the name of the game. Give leafy greens as a staple daily. Your Guinea pig needs about 1 cup or 8 ounces of their staple greens and appropriate veggies daily. For once-a-week treats, give a few small slices of your chosen vegetables as a treat.

Quick Tip

It's You may notice diarrhea for a short period of time when offering your guinea pig a new food.

Vitamins and Supplements

There are many supplements that you can add to your Guinea pig's diet, but it's important to be careful about what you give your piggies. Here are some of the most important supplements for Guinea pigs:

  • Vitamin C and calcium: Vitamin C is an antioxidant that helps keep your pet healthy from the inside out. Calcium is necessary for strong bones, which are especially important for Guinea pigs because they're prone to developing osteoporosis.
  • Omega-3 fatty acids: Omega-3 fatty acids are essential for brain and heart health, but most diets don't contain enough of them. Adding more omega-3s to your guinea pig's diet can help keep them sharp and healthy throughout their life.
  • Iron and B12 vitamins: Iron deficiencies can lead to anemia in humans, but they can also cause serious health problems in animals like Guinea pigs. B12 helps with red blood cell production - another important aspect of overall health - so it's important to make sure that your pet gets enough of both nutrients in their diet.
Person petting guinea pig
Quick Tip

If your Guinea's commercial diet is fortified with vitamin C, you don't have to be concerned with this as much. If your cavy does need it, additional vitamin C can be provided directly to your pet rather than offering it in their food or water.

Offering a Multivitamin

Multivitamin and mineral wheels for Guinea pigs are a great way to help give your pet a balanced diet. They contain all the vitamins, minerals, and trace elements that your cavy needs to stay healthy. Multivitamin supplements come in liquid or powder form and can be mixed into water or food.

The amount you feed your Guinea pig will depend on its age, weight, and health status. Follow the instructions on the package for recommended feeding amounts. Multivitamins aren't necessary for healthy adult cavies because they get most of their vitamins from their diet, but they may help prevent deficiencies if you feed a poor quality diet or if your pet isn't eating well due to illness or injury.

Foods to Avoid

Guinea pig next to his food bowl

Guinea pigs can eat most fruits and vegetables, but a few can cause problems for them. Some foods, plants, and vegetables are actually toxic or very unhealthy for Guinea pigs, and feeding some of these could result in GI upset, so avoid these at all times:

  • Alfalfa hay. High in calories and calcium, which can lead to bladder stones and obesity.
  • Avocado. Some parts of the plant are toxic.
  • Bread or dairy. These have no nutritional value for cavies.
  • Iceberg lettuce. This lettuce type has no nutritional value.
  • Onions. These are toxic for Guinea pigs.
  • Meat of any kind. Guinea pigs are strict herbivores and should never be provided any sort of meat.
  • Mushrooms. Not all mushrooms are bad for cavies, but they don't need them, and some are dangerous.
  • Rhubarb leaves and stalks. These can make your cavy very sick.
  • Potatoes. All parts of the plant are dangerous for Guinea pigs.
  • All grains. These are not healthy for Guinea pigs.
  • Nuts and seeds. These pose a strong risk of choking, and may be toxic.
  • Beans and corn. The starch content isn't healthy for Guinea pigs.

This list doesn't include every type of food or plant that is unsafe for Guinea pigs to eat, so check with your veterinarian if you aren't sure. You should also be careful of providing your Guinea pig with plants from outside. When they are outdoors, you'll notice they enjoy eating the grass, especially dandelion greens. However, you need to ensure you're in an area free of herbicides and pesticides.

No Foods with Calcium Oxalate

Calcium oxalate is a type of calcium that can cause health problems in Guinea pigs. It is poorly absorbed and may lead to excess calcium buildup in the body. Excess calcium may cause mineral imbalances, which can lead to various conditions, including bladder and kidney stones, which are very painful. Some of these foods may contribute to bladder stone formation, so limit or exclude these if your cavy is prone to bladder stones. Foods with calcium oxalate include:

  • Pears
  • Rhubarb
  • Tomato
  • Beets
  • Cruciferous vegetables, including kale, spinach, and collards

How Often Guinea Pigs Eat

Guinea pigs should eat on a schedule. Aside from providing them hay at all times, they should be fed their commercial diet twice per day. Guinea pigs are opportunistic eaters and they will overeat if food is offered. Because they have a lot of carbs, overfeeding pellets can result in obesity, diarrhea, and flatulence.

Vegetables can be kept in their habitat all day. Discard the vegetables that remain after 12 hours, or when they appear to be soiled. Offer selected fruits as a weekly treat, in the appropriate amounts. Fresh water should be available at all times. Generally, this is provided in a water bottle. However, if your Guinea pig prefers to drink their water from a bowl, that works, too.

Maintaining Healthy Nutrition

Make sure that your Guinea pig has clean, fresh water, fresh hay, some vegetables and pellets to help them maintain a healthy diet. In order for them to thrive, it is important that their nutritional needs are met. If their nutritional needs are not met, they could develop health conditions requiring veterinary care.

Guinea Pig Diet Guide: Complete Health and Nutrition for Cavies