Blue Tongue Skink Feeders: Discoid Roaches, Fruit Flies, or Crickets?
I keep blue tongue skinks, and the question of which feeder insect to use comes up constantly: discoid roaches, fruit flies, or crickets? The honest answer is that this is barely a three-way contest. One of these isn't a real option for a skink at all. Here's how they actually compare, with the source-article errors corrected.
What a blue tongue skink needs
Blue tongues (Tiliqua spp.) are hardy, omnivorous lizards from Australia, Indonesia and New Guinea. Unlike a gecko or anole, they are not insect specialists — in the wild they eat insects, snails, carrion, flowers and fruit. In captivity I aim for roughly:
- ~50% animal protein — feeder insects, plus occasional lean cooked meat, egg, or a high-quality wet dog food / commercial skink diet.
- ~40-50% vegetables, mostly calcium-rich leafy greens.
- A small amount of fruit as a treat.
Across all of it: calcium with D3, because metabolic bone disease (MBD) is the number-one preventable killer in captive skinks. Now to the feeders.
Fruit flies: not a skink food
Let me get this one out of the way. Fruit flies are a fine feeder — for dart frogs, mantellas, and tiny juvenile amphibians. For a blue tongue skink they make no sense:
- Size. Adult blue tongues have broad, crushing jaws built for snails and roaches. It would take an absurd number of fruit flies to equal one meal. Even hatchlings are too large to benefit.
- Nutrition. Fruit flies are mostly water with little protein or fat per insect.
- Logistics. They're fast, they fly, and they'll colonize your kitchen before they feed your skink.
Verdict: skip them entirely for blue tongues. They are not "for very young skinks" — even hatchlings should eat appropriately sized roaches and small crickets.
Discoid roaches: the staple
Discoid roaches (Blaberus discoidalis) are my default staple, and they're commonly confused with dubia roaches (Blaptica dubia) — different species. Discoids are a non-climbing, non-flying tropical roach from Central and South America. Their strengths:
- High protein, roughly 20-23%, with moderate fat (~9-11%) — lean enough to avoid the obesity that fatty feeders cause.
- Low chitin and soft-bodied, so they digest easily and reduce impaction risk — important for a slow-digesting skink.
- Quiet, odorless, and easy to keep; they breed readily in a warm bin.
- Can't climb smooth surfaces and can't fly, so a smooth-sided container contains them, and they can't infest a temperate home. (That last point is also why they're legal in places where dubia are restricted.)
One correction to the usual marketing: discoid roaches do not have a "favorable" calcium-to-phosphorus ratio. Like nearly every feeder insect they are phosphorus-heavy. The fix is the same as for any feeder — dust with calcium and gut-load before feeding. Their real edge is protein, digestibility, and convenience, not minerals.
Source them captive-bred from All Angles Creatures' discoid roach collection rather than wild-collecting, which risks pesticides and parasites.
Crickets: the workable backup
Crickets are the classic feeder and a perfectly good rotation insect:
- ~20% protein, ~6% fat, gut-loadable, and widely available in every size from pinhead to adult.
- Active movement triggers a skink's hunting response, which is good enrichment.
Their downsides are practical: they're noisy, they smell, they die off fast, and loose ones hide and stress the skink (and can nibble it). Like roaches, they're phosphorus-heavy and need gut-loading plus calcium dusting. I treat crickets as a fine supplement to a discoid-based diet rather than the foundation.
Side by side
| Feeder | Fit for blue tongues | Protein | Key strength | Key drawback |
|---|---|---|---|---|
| Discoid roach | Excellent staple | ~20-23% | Soft, low-chitin, quiet, contained | Phosphorus-heavy; dust it |
| Cricket | Good rotation | ~20% | Available, active, gut-loadable | Noisy, smelly, short-lived |
| Fruit fly | Not suitable | low | None for a skink | Far too small; escapes |
Feeding routine that works
- Size: no bigger than the width of the skink's head. Smaller for juveniles.
- Gut-load roaches and crickets 24-48 hours ahead on carrots, squash, leafy greens, or commercial chow.
- Dust feeders with calcium + D3, especially if UVB is marginal.
- Schedule: juveniles daily, adults every 2-3 days. Pull uneaten insects so they don't stress or bite the skink.
- Round it out: pair the protein with collard, mustard and dandelion greens (skip spinach and iceberg — oxalates and empty calories), plus squash and carrots, and a little berry/mango/papaya as treats.
The bottom line: build the diet on discoid roaches, rotate in crickets for variety and enrichment, and forget fruit flies entirely — they're the wrong tool for this animal.
For a deeper look at one of these matchups see discoid roaches vs house flies, or to actually keep a roach colony alive read how to keep discoid roaches alive. On preventing MBD, the Merck Veterinary Manual on reptile nutrition is the reference I trust.