Waxworms vs. Discoid Roaches for Blue-Tongue Skinks: Staple or Treat?
People ask me this one constantly, and the honest answer disappoints anyone hoping for a tie: for a blue-tongue skink, discoid roaches and waxworms aren't two options on the same shelf. One is a staple-class feeder you can build a diet around. The other is a fat bomb that belongs in the "treat" drawer next to the dog biscuits. Treating them as interchangeable is how skinks get fat, get liver disease, and get so hooked on the junk food they refuse everything else.
So this isn't really a "which one wins" article. It's a "what is each one actually for" article. Discoid roaches (Blaberus discoidalis) are the protein backbone you reach for several times a week. Waxworms — the larvae of the wax moth, Galleria mellonella — are a once-in-a-while reward and a genuinely useful tool for a skink that needs to put on weight. Get that distinction right and both earn a place. Get it wrong and one of them slowly hurts your animal.
First, what a blue-tongue skink actually eats
Before either insect makes sense, you have to remember what a blue-tongue skink is: an omnivore, not an insectivore. In the wild they're slow-moving ground foragers that eat a genuinely mixed bag — snails, insects, carrion, plus a real amount of plant matter, greens, and fallen fruit. That mix is the whole point. A bearded dragon juvenile is a bug-eating machine; a blue-tongue skink is closer to a tiny, scaly opportunist that eats whatever the forest floor offers.
In captivity that translates to a diet that's roughly part animal protein and part plant matter — leafy greens, squash, other veg, and a little fruit as a treat. Insects are one slice of the protein half, not the whole meal. So when we compare waxworms and discoids, we're only ever talking about how to fill that insect slice well. Neither one is "the diet."
Two facts about skinks make the fat question urgent. First, adults eat infrequently — every few days, not every day — so each meal carries real weight in the overall balance; you don't get many feedings to dilute a bad one. Second, blue-tongue skinks are strongly obesity-prone. They're built to survive lean stretches, so in a tank with a full bowl and no predators, they pack on fat fast. A high-fat feeder that would barely register on a fast-burning animal becomes a genuine health problem on a skink.
That's the lens for everything below. Calories your skink can't burn don't just sit there — they become body fat and fatty deposits in the liver.
The numbers that decide everything
Here's the comparison stripped to what matters. Treat these as approximate, as-fed figures — real values swing with diet, life stage, and source — but the relationships are rock-solid and they're what should drive your feeding.
| Feeder | Protein | Fat | Moisture | Calcium | Best role |
|---|---|---|---|---|---|
| Discoid roach (Blaberus discoidalis) | High (~20%) | Low (~6–7%) | ~60–65% | Phosphorus-heavy, dust needed | Staple |
| Waxworm (Galleria mellonella) | Low-ish (~14–15%) | Very high (~20–25%) | ~60% | Low, phosphorus-heavy | Occasional treat |
Look at the fat column. A waxworm carries three to four times the fat of a discoid for less protein. That single relationship is the entire argument. One feeder delivers lean protein to build and maintain a body; the other delivers a slug of fat with a modest protein chaser. On an animal that already tends toward obesity and only eats every few days, that gap is decisive.
Discoid roaches: the staple
Discoids are the feeder I'd build a blue-tongue skink's insect rotation around, and the reason is mostly that table above: ~20% protein on only ~6–7% fat, with a high moisture content (~60–65%) that's gentle and hydrating. They're lean protein in a bug-shaped package, which is exactly what an omnivore that overfattens easily needs from its insects.
A few practical things make them easy to live with:
- Low chitin, easy to digest. Discoids have a softer, lower-chitin body than crickets, so they go down and digest cleanly — less risk of the gut-packing you worry about with hard-shelled feeders. (You'll see claims that their "tough exoskeleton adds fiber." For a skink that's a non-feature at best; the real story is that they're easy on digestion.)
- They don't climb smooth surfaces. Drop discoids in a smooth feeding bowl and they stay put instead of marching out across the tank. Less chasing, less stress, less mess.
- Slow movers and quiet. They're easy for a deliberate skink to catch and they don't smell or chirp the way crickets do.
The one thing discoids are not is a calcium fix. This is where I'll correct a myth that gets repeated a lot, including in the article this guide grew out of: discoids do not have a favorable calcium-to-phosphorus ratio. Like nearly every feeder insect, they're phosphorus-heavy — there's far more phosphorus than calcium in the bug. Gut-loading helps the overall nutrition, but it does not flip that ratio. You still dust discoids with calcium, the same as you would crickets or any other feeder. Anyone telling you discoids let you skip calcium is wrong, and following that advice is a fast route to metabolic bone disease.
If you keep skinks and want a clean, well-started supply to feed from (or to start a small colony), All Angles Creatures stocks healthy discoid roaches sized for both direct feeding and seeding a bin.
Sizing and feeding discoids
- Match the feeder to the skink's head. The rule of thumb across reptiles holds here: no feeder wider than the space between the eyes, and for a chunky-headed skink that still means picking nymphs or adults that aren't oversized. When in doubt, smaller.
- Frequency follows the animal. A growing juvenile gets protein more often; a healthy adult eats every few days and on those days insects are part of the plate alongside greens. Discoids can headline the insect portion of most of those meals without guilt — that's what "staple" means.
- Always dust, and watch the body. Plain calcium at most feedings, calcium-plus-D3 on the schedule your UVB setup dictates, and a multivitamin sparingly. Then watch your skink's body condition and adjust — a feeder being "lean" doesn't mean unlimited.
For how discoids stack up against soft-bodied worms when hydration is the goal rather than fat, see my companion piece on discoid roaches vs. nightcrawlers for skink health — that's a different axis than the one we're on here.
Waxworms: the treat (and a real tool)
Now the fun one — and the one people abuse. Waxworms are the larval stage of the wax moth, Galleria mellonella. They're soft, plump, pale, and they wiggle in a way skinks find irresistible. They are also, nutritionally, almost pure fat by feeder standards: roughly 20–25% fat as-fed, with low protein and very little usable calcium and a phosphorus-skewed ratio just like the discoid. There is no version of the math where a waxworm is a staple.
So why keep them around at all? Because used correctly, that fat is a feature, not a bug:
- Appetite-tempter. Their sweet, fatty taste is the single best motivator I know for a fussy skink. A skink that's ignoring food, or one you're transitioning to a new item, will often take a waxworm — and that interest can be used to kick-start a meal.
- Putting weight on a skink that needs it. For an underweight, recovering, or convalescing animal, a calorie-dense soft feeder is genuinely useful for adding condition quickly. Their softness also makes them easy on a weak or recovering animal that's struggling with tougher prey.
- An occasional reward. A couple of waxworms now and then, folded into an otherwise balanced meal, does no harm to a healthy skink and adds a little variety and enrichment.
That's the whole legitimate use list. Note what's not on it: "regular protein source," "weekly staple," "main insect."
Why the fat is actually dangerous here
It's worth being blunt about what overusing waxworms does, because "they're a bit fatty" undersells it:
- Obesity. On an animal that overfattens this easily, a high-fat feeder on repeat puts on weight fast, and a fat skink is a sick skink waiting to happen.
- Fatty liver disease (hepatic lipidosis). Chronic excess dietary fat drives fat deposition in the liver — a serious, sometimes fatal condition that builds quietly over months. This is the real long-term cost of "he just loves them."
- Treat-addiction / hunger strikes. This is the sneaky one. Skinks that get used to waxworms will refuse better food, holding out for the junk. I've watched keepers panic-feed waxworms because the skink "won't eat anything else" — which only trains the behavior deeper. A healthy skink will not starve itself; cut the waxworms, offer the proper food, and wait it out. (If you're keeping waxworms alive and on hand, see how to keep waxworms alive after purchase so a tub doesn't all pupate into moths before you've used your handful.)
A sane waxworm frequency
For a healthy adult skink: a few waxworms at most once every week or two, mixed into a normal meal — never their own dedicated feeding day, never the main item. For an underweight or recovering skink: you can lean on them harder and more often for a short stretch to add condition, then taper off the moment the weight is back. The test is simple — if waxworms are showing up on a schedule rather than as an exception, you're using them wrong.
The verdict, plainly
If someone makes me pick one word for each: discoid = staple, waxworm = treat. Don't overthink it past that.
- For the everyday insect protein in a blue-tongue skink's omnivore diet, discoid roaches are the right tool — lean, digestible, hydrating, and easy to keep. Dust them with calcium; they don't excuse you from that.
- For an occasional reward, an appetite jump-start, or putting weight on a skink that's too thin, waxworms are a genuinely useful treat — used rarely, deliberately, and never as a habit.
- And remember the frame the whole comparison sits inside: insects are only half of a blue-tongue skink's diet. The leanest, best-dusted discoid in the world still needs to share the plate with greens, veg, and variety. Get the whole diet right and the waxworm-vs-discoid question takes care of itself — the staple does the heavy lifting, the treat stays a treat, and your skink stays lean, strong, and willing to eat its vegetables.