"Frogs and toads" covers an enormous spread of animals, from a dart frog that eats things you can barely see to a horned frog that will attempt anything it can fit in its mouth. What they have in common is that almost all of them eat live moving invertebrates, that almost none of those invertebrates are nutritionally complete on their own, and that mouth width decides everything. This guide works through feeder choice by frog size, then covers supplementation, what to avoid, and how to order. It is general husbandry, not veterinary advice.
Size decides the feeder, not the species name
The most useful way to think about amphibian feeding is by the animal's mouth rather than by its common name. Published guidance puts prey at no larger than the width of the frog's head, and for toads no larger than the width of the mouth. That single constraint sorts most of the decisions for you.
| Animal size | Typical examples | Feeders that fit |
|---|---|---|
| Very small | Dart frogs, young froglets of most species, small tree frogs | Springtails and flightless fruit flies. Crickets are usually too large, and keepers report that cricket legs can injure a small frog. |
| Small to medium | Tree frogs, fire-bellied toads, most juveniles | Small to medium crickets, small roach nymphs, small worm feeders. |
| Large | Adult White's tree frogs, adult toads, horned frogs | Adult crickets, larger roaches, earthworms, hornworms, night crawlers. |
Very small amphibians are the group most people underestimate. A newly morphed froglet or an adult dart frog is a genuinely tiny animal, and the feeders that suit it are cultures rather than counted insects. Springtails are often kept alongside isopods as a clean-up crew, and both do double duty in a bioactive setup as food and as janitors. We sell fruit flies, but not springtails or isopods.
Which feeders work, and where
Crickets
Crickets are the default feeder for most frogs and toads above dart-frog size. They move constantly, which matters because frogs strike at movement and largely ignore food that sits still. The size ladder is fine enough to follow an animal from small juvenile to adult. They are calcium-poor relative to phosphorus, so they need dusting, and adult crickets will chew on a resting frog if left loose overnight.
We do not sell crickets. Dubia roaches are what we sell instead.
Roaches
Feeder roaches suit larger frogs and toads well. They carry more meat per insect than a cricket, they store far better, and they are quiet. Nymphs cover the smaller sizes. The one caveat is movement: roaches tend to head for cover rather than wander in the open, so in a planted enclosure they can disappear before the frog notices them.
Earthworms and night crawlers
Worth calling out separately because of a genuine nutritional quirk. The Merck Veterinary Manual notes that most invertebrates do not have the right calcium-to-phosphorus ratio to support healthy bone growth in amphibians, and names earthworms as the exception. For terrestrial frogs and toads big enough to take them, they are one of the few feeders that is not working against you on minerals.
Worm feeders and soft-bodied larvae
Most of the worm feeders are useful in rotation rather than as the base of a diet. Hornworms are mostly water and are useful for a frog that needs the fluid. Waxworms are very fatty and calcium-poor, and amphibians in captivity are already prone to putting on weight, so they belong in the occasional column. Mealworms have a hard exoskeleton relative to their body mass and are a poor choice for small amphibians in particular.
Aquatic and larval amphibians
Fully aquatic species and larvae are a different problem again. Bloodworms and black worms are the standard fare there rather than terrestrial feeder insects, and species that eat vertebrates may need small fish. That is far enough from feeder insects that it is worth taking specific advice on the species you keep.
Prey size and the mouth width rule
The rule is simple and it is the one thing not to be relaxed about.
- Frogs: nothing wider than the frog's head.
- Toads: nothing wider than the toad's mouth.
- Judge width, not length. An earthworm is long and narrow. An adult roach is short and broad. They are not equivalent.
- Small amphibians need cultures, not insects. If you are counting individual feeders for a dart frog, the feeder is probably too big.
- Horned frogs will take prey that is bad for them. Willingness is not a sizing guide in a species that ambushes anything that moves.
Size names are not standardized across the trade, which matters more for amphibians than for most groups because the small end of the range is where the errors happen. For roaches, the dubia roach size chart gives the actual length in inches behind each size name.
Supplementation, and the vitamin A problem
Feeder invertebrates are not a complete diet for amphibians. Two things fix that.
Gut loading. Merck's guidance is to feed prey a calcium-rich commercial diet 48 hours before it goes to the amphibian. Published amphibian and reptile care sheets commonly give a window of roughly 24 to 72 hours. Either way, this is done before dusting, not instead of it.
Dusting. Coating the prey in powdered calcium, or a multivitamin containing vitamin D3 and calcium, immediately before feeding. Frequency varies by species and by setup and is a question for a vet with amphibian experience.
Vitamin A deserves its own paragraph, because it is the amphibian-specific deficiency and it is not obvious. Hypovitaminosis A in captive amphibians is associated with what keepers call short tongue syndrome: the tongue loses the sticky mucus coating that lets it pick up prey, so the animal strikes accurately and comes back with nothing. The tongue is not actually short. Amphibian supplements typically specify retinol, preformed vitamin A, rather than relying on beta-carotene. Excess vitamin A causes its own problems, so the dose and frequency are a veterinary question, not something to work out from a shop page.
For the comparative figures behind the feeder choices, the nutrition table in our bearded dragon feeder guide puts moisture, protein, fat and calcium-to-phosphorus ratio side by side, with sources. The guide on gut loading feeder insects covers what to feed the insects first.
What to keep out
- Fireflies. Cornell University biologists warned in 1999 that fireflies were killing zoo and pet lizards. The toxins involved are cardiotoxic, and keepers treat fireflies as off limits for amphibians too. Never feed them, and think about where an enclosure sits if you keep frogs outdoors in firefly season.
- Wild-caught insects. Pesticide residue and parasites. Amphibian skin is permeable, which makes chemical exposure a larger concern here than in reptiles.
- Anything left loose overnight. Crickets will bite a sleeping frog.
- Prey over the mouth-width rule, especially with ambush feeders that will take it anyway.
- Routine vertebrate prey for species that do not need it. Rodents in particular are commonly overfed to horned frogs, and obesity is a real problem in captive amphibians.
Ordering for amphibians
Two things make amphibian feeder buying different. The first is that the small end of the range is culture-based rather than count-based. Springtails and fruit flies are maintained as ongoing cultures rather than bought by the tub each week, so the buying pattern is closer to starting something than restocking it.
The second is that many frogs and toads eat two or three times a week rather than daily, which means the feeders spend more time in your care than in the animal. That makes storage quality the thing worth optimizing for. A feeder that has sat unfed for a week is a poorer meal than the same feeder gut-loaded the day before, and it also undoes the 48-hour loading window entirely.
Of the feeders covered here, we sell fruit flies, dubia roaches, hornworms and the worm feeders, all in the feeders collection. We do not sell earthworms, night crawlers or aquatic live foods. When a box arrives, what to do when your feeders arrive covers the unpacking.
This guide describes feeding a healthy animal. A frog that is striking at prey and missing, is losing weight, is bloated, or has become lethargic needs a vet with amphibian experience. Amphibians deteriorate quietly and are harder to treat late than early.