What Should Pet Frogs Eat? Why Crickets Alone Aren't Enough

Crickets alone are not a complete diet for a pet frog. Like most feeder insects, they are low in calcium and vitamin A, so frogs need gut-loaded, dusted prey, a mix of insect types, the right portion sizes, and no wild bugs. Here is what veterinary and nutrition research shows.

A frog capturing an insect in a natural grassy habitat, illustrating how frogs hunt live prey.
Photo: Shreesha Sharma / Wikimedia Commons. Licensed under CC BY-SA 4.0. Original photograph, unmodified.

Every few days, you tip a handful of crickets into the tank. The frog lunges, swallows, and waits for more. It looks well fed.

A frog can eat eagerly and still be missing nutrients. Some deficiencies take months to show, and by then the bones or tongue may already be affected.

This guide explains why a cricket-only diet falls short, what to feed instead, and how to supplement correctly. Needs vary by species and age, so confirm the details with a veterinarian who treats amphibians.

What do pet frogs eat?

Mostly live animal prey, usually insects and worms. The Merck Veterinary Manual says most amphibians need live food. Its list includes earthworms, bloodworms, blackworms, fruit flies, fly larvae, mealworms, and crickets. Merck adds that some larger species may also take small fish or newborn rodents.

PetMD describes most frogs as insectivores that eat live invertebrates in the wild. What they need from their prey depends on the species. A tiny dart frog eats fruit flies and other very small insects, a White's tree frog eats crickets and roaches, and a large horned frog can swallow much bigger prey.

Why aren't crickets alone enough?

Because crickets, like most insects, have much more phosphorus than calcium. Most insects lack a mineralized skeleton. A 2021 review in the Journal of Insects as Food and Feed by Dennis Oonincx and Mark Finke reports that calcium in most insects is typically below 0.3% of dry matter.

A widely cited 2002 analysis of commercially raised feeder insects by Finke, summarized in a 2019 Louisiana State University thesis, found adult house crickets had roughly 7 times more phosphorus than calcium. Mealworms had about 17 times more, and superworms about 13 times more. Merck's professional guidance links an inverse ratio, with more phosphorus than calcium, to metabolic bone disease in amphibians.

Calcium is not the only gap. Merck explains that amphibians cannot make carotenoids, including vitamin A, so they must get them from food. Plain crickets supply very little. A 2014 review of cricket studies in the journal Zoo Biology concluded that gut-loading and dusting appear necessary to support the nutritional health of amphibians.

What happens when a frog lacks calcium or vitamin A?

Calcium problems can deform bones; vitamin A problems can stop a frog from catching food.

  • Metabolic bone disease (MBD): Merck calls this frequent in captive amphibians. It results from too little calcium and vitamin D3, an inverse calcium-to-phosphorus ratio, and inadequate UVB light. Signs include a soft or misshapen lower jaw, broken bones, a curved spine, and, later, muscle spasms and bloating.
  • Short tongue syndrome: Merck links vitamin A deficiency to lethargy, wasting, and an inability to use the tongue to catch prey. In a book chapter on the condition, veterinary pathologist Allan Pessier describes affected Wyoming toads that tried hard to catch prey but failed, and severe cases that needed hand feeding.

Both conditions need a veterinarian. Merck notes that treatment may include supplements, vitamin injections, and better lighting. Do not try to treat suspected MBD at home by adding extra vitamins, because too much of some vitamins can also cause harm.

How do you gut-load and dust feeder insects?

Gut-loading feeds the insect; dusting coats it. Both are needed in most cases.

  • Gut-loading: feed the insects a nutritious, calcium-rich diet before offering them to the frog. Merck says 48 hours; the Royal Veterinary College (RVC) in London suggests a complete invertebrate diet for 24 hours. In a study presented to the Nutrition Advisory Group of the Association of Zoos and Aquariums, crickets fed a high-calcium, vitamin-A-rich diet reached target levels by day two.
  • Dusting: shake insects in a powdered calcium or multivitamin supplement just before feeding. The RVC says to feed dusted insects immediately. A 2014 study in the Journal of Zoo and Aquarium Research found that dusting raised crickets above a 1:1 calcium-to-phosphorus ratio for only up to about 5.5 hours, and the effect was weaker in adult crickets.
  • How often: LafeberVet's care sheets suggest dusting two to three times a week for juveniles and once a week for adults, depending on species. The RVC alternates a calcium powder with a vitamin and mineral powder.

Products differ in their calcium, vitamin D3, and vitamin A content. Ask your veterinarian which supplements and schedule fit your frog, especially if it has no UVB light.

Which feeder insects make a good mix?

Rotate several types, and treat fatty larvae as occasional foods.

  • Crickets and roaches: common staples for medium frogs. Neither is complete on its own.
  • Earthworms: Merck describes them as the exception among invertebrates for calcium content, though published analyses still show more phosphorus than calcium. Use captive-raised worms, not ones from the yard.
  • Black soldier fly larvae: unusual among insects because they can contain high levels of calcium, according to Oonincx and Finke. They work as part of a mix.
  • Fruit flies: useful for very small frogs and froglets.
  • Mealworms, superworms, and waxworms: poor calcium balance, and waxworms are high in fat. PetMD warns that feeding mealworms exclusively and in large amounts can lead to digestive problems such as constipation.

How big should prey be, and how often should a frog eat?

Smaller than you think, and less often than many owners feed. The RVC advises that an insect should never be bigger than the distance between the frog's eyes, to reduce the risk of blockage. Large-mouthed species such as horned frogs are an exception and take larger prey.

Frequency depends on age and species. For White's tree frogs, LafeberVet suggests feeding juveniles daily and adults two to three times a week, while the RVC says adults every other day. For pacman frogs, PetMD recommends adults eat only once or twice a week.

Merck describes obesity in amphibians as a disease, caused mainly by overfeeding, and notes that many amphibians keep eating as long as food is available. The RVC suggests removing live food that is not eaten within 30 minutes.

Can frogs eat wild bugs or mice?

Skip wild-caught insects, and keep rodents rare or off the menu.

Insects from the yard can carry parasites or pesticide residue. Never feed fireflies. In 1999, Cornell biologists warned that fireflies, which contain toxins called lucibufagins, had killed pet lizards and, in one owner's report, White's tree frogs.

Mice are a common question for owners of large frogs. Merck's pet owner guidance says some species may need newborn mice or rats, but other veterinary sources are more cautious. LafeberVet's horned frog sheet links rodent-based diets to obesity and corneal lipidosis, a fatty clouding of the eye, and PetMD limits mice to an occasional treat once or twice a month. Insects and worms should be the main diet.

When should you call a veterinarian about your frog's diet?

Call when eating, movement, or body shape changes. Contact an amphibian veterinarian if you notice:

  • A soft, bent, or swollen lower jaw, a curved back, or trouble moving the legs.
  • Repeated missed strikes, or a frog that tries to eat but cannot get prey into its mouth.
  • Weight loss, or loss of interest in food for more than a few feedings.
  • A belly that stays swollen, or no droppings after a large meal.
  • Cloudy eyes or rapid weight gain.

Bring a list of the insects you feed, how you gut-load and dust them, and the supplement labels. Habitat problems can also cause appetite loss; see our care and habitats section.

The bottom line

Crickets can be part of a frog's diet, but not all of it. Gut-load feeder insects for a day or two, dust them right before feeding, rotate several types, and size prey to the frog. Feed adults sparingly, remove leftovers, and never offer fireflies or bugs from outdoors.

Ask your veterinarian to set the supplement plan, and watch for jaw, posture, and tongue problems. For care basics by species, browse our amphibians section.

Sources & further reading

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