If our feeding chart answers “what do I feed this thing?”, this guide answers the question that quietly stresses out every new keeper: how often? Feed too much and you risk an over-plump, rupture-prone pet; feed too little and growth stalls. The good news is that invertebrates are forgiving, and once you understand the few things that actually change feeding frequency — age, temperature, body condition, and molting — you’ll never second-guess a feeding day again.
Quick answer: Feeding frequency depends mostly on age. Babies eat small meals often (every 1–3 days); adults eat larger meals rarely (weekly, or even monthly for big tarantulas). Detritivores like isopods graze constantly and need almost no scheduling. Warmer temperatures speed up metabolism (feed a little more), and any pet in pre-molt should be fed nothing at all. When in doubt, read the abdomen, not the calendar — plump and rounded means you’re getting it right.
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Frequency by Pet Type
Jumping spiders
The single biggest factor is age. Spiderlings burn through energy growing fast and should eat every 1–2 days. Juveniles settle to every 2–3 days. Adults need just one or two meals a week (every 3–7 days). One or two appropriately sized feeders per sitting is plenty.
Tarantulas
Tarantulas are the masters of the long fast. Fragile slings benefit from frequent small meals — two to three times a week, or essentially as often as they’ll eat. Adults are astonishingly low-maintenance: anywhere from weekly to monthly, with some large, slow-metabolism species happy on just four or five crickets a month. A tarantula refusing food for weeks is usually normal (often pre-molt), not starving.
Praying mantises
Nymphs eat every 2–3 days (a young mantis might take 5–10 fruit flies in a sitting); adults eat every 2–4 days. Mantises are great self-regulators — offer food whenever the abdomen isn’t visibly full, and stop when it plumps up.
Isopods & other detritivores
Here “frequency” barely applies. Isopods, millipedes, and springtails graze continuously on leaf litter and decaying wood that’s always available in the enclosure. The only thing you schedule is a protein top-up (a pinch of fish flake or dried shrimp) once or twice a week, plus a constant calcium source. They are about as close to “feed and forget” as the hobby gets.
The everyday feeder: small crickets cover most scheduled feedings for spiders and mantises — easy to size down for juveniles and to gut-load before a feeding day.
The Four Things That Change Frequency
1. Age
As you’ve seen, this is the headline. Young animals are growing and eat small-and-often; mature animals coast on much less. Scale frequency down as your pet grows up.
2. Temperature
Invertebrates are ectotherms — their metabolism rises and falls with the ambient temperature. A pet kept warm digests faster and gets hungry sooner; a cool enclosure slows everything down, including appetite. If your room runs cold in winter, don’t be surprised when feeding intervals naturally stretch out. Knowing your actual enclosure temperature takes the mystery out of a pet that’s “suddenly not interested.”
Know your numbers: because temperature drives appetite, a simple digital thermometer-hygrometer is the easiest way to understand your pet’s feeding rhythm — and to rule out “too cold” before you worry about “sick.”
3. Body Condition
The abdomen is your truest gauge. Plump and rounded means your current schedule is perfect. Looking shrunken or wrinkled? Feed more often (and check hydration). Tight, shiny, and oversized? Ease off — an over-full abdomen is fragile and may also mean a molt is coming. Learn your individual pet’s “just right” and adjust from there.
4. Molting
This is the big exception to every schedule: a pet in pre-molt should not be fed, and a freshly molted one shouldn’t eat until its new fangs or mouthparts have hardened (a few days for small species, up to two weeks for adult tarantulas). Food refusal almost always means a molt, not a problem — so before you worry, read our molting guide and health guide.
Building a Simple Feeding Routine
You don’t need a spreadsheet. A routine that works for most keepers:
- Pick a regular feeding day (or two) based on the frequency above for your pet’s age.
- Offer one or two correctly sized feeders — never bigger than the abdomen — and watch the catch.
- Remove uneaten prey within a day. A leftover cricket can stress or even injure a pet, especially one heading into a molt.
- Check the abdomen each feeding and nudge frequency up or down.
- Pause entirely at the first signs of pre-molt, and resume only once the new exoskeleton has hardened.
Overfeeding vs. Underfeeding
It’s natural to want to feed constantly — hunting is the best show in the enclosure — but “power-feeding” to grow a pet quickly leaves the abdomen dangerously large and prone to rupture from a fall. Underfeeding is the gentler error: a slightly lean invertebrate simply eats next time. If a pet has genuinely fallen behind (a shrunken abdomen after a fast or a rough molt), a richer feeder like a waxworm can help it rebound — just treat it as an occasional boost, not the new normal.
For a rebound meal: waxworms are rich and fatty — a useful once-in-a-while pick-me-up for an underweight adult, best offered sparingly rather than on a schedule.
Frequently Asked Questions
How long can my invertebrate go without food?
Far longer than you’d think. Adult tarantulas can fast for weeks or even months safely, and most invertebrates handle a missed meal easily. Water is the real priority — dehydration is far more dangerous than a delayed feeding.
Why has my pet stopped eating?
The most common reasons are an approaching molt or a cooler enclosure slowing its metabolism. Both are normal. Keep water available, hold off on feeding, and check our molting and health guides before worrying.
Should I feed more in summer than winter?
Often, yes. Warmer temperatures raise metabolism and appetite, so feeding intervals naturally shorten in summer and lengthen in a cold winter room. Let body condition fine-tune the schedule.
How many feeders per meal?
For most spiders and mantises, one or two correctly sized feeders per feeding is ideal. It’s better to offer a little and top up next time than to overload the abdomen in one go.
Explore Related Guides
- Invertebrate Feeding Chart — the full what-to-feed breakdown
- Invertebrate Molting Guide
- Invertebrate Health & Signs of Illness
- The Invertebrates Care Hub
Be good. Do the research. Love your weirdo.