MMatt Goren
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Feeder Insects📚 In-depth guide

Butterworms vs. Discoid Roaches for Blue Tongue Skinks: Staple vs. Treat, Decided

By Matt Goren · Updated June 25, 2026

I've fed blue tongue skinks for years, and the butterworm-versus-discoid-roach question is one I get constantly — usually phrased as "which one should I use?" as if you have to pick a side. You don't. These two feeders aren't competitors for the same job; they're tools for two different jobs. One is the lean, breedable staple protein you build the diet around. The other is the rich, irresistible treat you keep on hand for picky eaters and weight gain. Confuse the two — feed the treat like a staple — and you end up with a fat, unhealthy skink. Use each for what it's actually good at and you get a thriving animal.

This is the complete breakdown: what a blue tongue skink's diet actually needs, an honest nutritional profile of each feeder, the calcium and digestibility realities (including a couple of myths I'm going to correct head-on), how to store and handle both, exact feeding schedules by life stage, the common mistakes that hurt skinks, and a clear verdict you can act on. Read it once and you'll never second-guess which worm or roach goes in the bowl again.

What a blue tongue skink's diet actually needs

Before you can judge any feeder, you have to know what you're feeding. Blue tongue skinks are omnivores, and this is the single most important fact about their nutrition — it's what separates them from a bearded dragon or a leopard gecko and it's what most "best feeder" debates ignore.

In the wild, blue tongues are opportunistic ground foragers. They eat insects, snails, carrion, and a surprising amount of plant matter — flowers, fallen fruit, leaves, and shoots. That omnivory has to be recreated in captivity, and the proportions shift as the animal ages.

Here's the framework I work from:

  • Protein (animal matter): The smaller share for an adult, the larger share for a baby. This is where feeder insects, lean meats, and the occasional egg live. Hatchlings and juveniles are growing fast and lean heavily on protein; adults need much less.
  • Vegetables (plant matter): The backbone of an adult's diet — roughly 40% for a juvenile climbing toward 50–60% for an adult. Dark leafy greens are the core: collard greens, mustard greens, dandelion greens, and turnip greens, which bring calcium and stay low in oxalates. Add squash, bell pepper, carrot, and green beans for variety.
  • Fruit: A small treat slice, maybe 10% of the diet at most, because of the sugar. Berries, mango, papaya, and melon are good occasional additions for vitamins and a bit of hydration.
  • Calcium and vitamins: Dusted onto food, because no whole-prey or produce diet hits the calcium target on its own. Calcium (often with D3, depending on your UVB setup) plus a sparing multivitamin.

A few hard "never" foods, because they matter: avocado, onion, garlic, and rhubarb are toxic and have no place in the diet. Skip high-oxalate greens like spinach and kale as staples — the oxalates bind calcium and work against you.

Now hold that framework in mind, because everything that follows is about where butterworms and discoid roaches fit inside it. Spoiler: the vegetables are doing most of the work for an adult, and the feeder you pick is the protein accent — which is exactly why getting that accent right (lean staple, occasional treat) matters so much.

Why the protein source you choose matters so much

You might reasonably ask: if greens are 50–60% of an adult's diet, does the feeder insect really matter that much? It does, for three reasons.

First, protein quality drives growth and repair. Amino acids from animal protein build muscle and support healing in a way plant matter doesn't fully replace. A growing juvenile especially needs that.

Second, fat content quietly decides body condition. A skink eating a lean staple protein stays in good shape. A skink eating a fatty feeder as its staple slides into obesity and fatty-liver disease over months — and you often don't notice until it's a problem.

Third, the feeder you pick is the calcium-delivery vehicle. A soft, gut-loadable, dustable feeder lets you load calcium and nutrients into your skink. A feeder you can't gut-load (like butterworms) limits you to what's already inside it plus a dusting.

That's the lens. Let's profile each feeder honestly against it.

Butterworms: the high-fat treat, profiled honestly

Butterworms are the larvae of a Chilean moth, Chilecomadia moorei. In the wild they bore into the trembling-tree (Tebo) shrubs of Chile, and they get their name from their soft, plump, butter-colored bodies and faintly sweet smell. That smell is not incidental — it's a big part of why skinks find them so hard to resist.

Here's the thing keepers most need to understand about butterworms, and the source article I'm rebuilding this from glossed over it: butterworms sold in the United States are irradiated. They're treated with low-level radiation before import, which sterilizes them so they cannot pupate into moths or breed. This is a regulatory requirement to prevent a non-native moth from establishing here. The practical consequence for you is simple but important — you cannot culture butterworms at home. There is no colony to start, no breeding to manage. They are a buy-and-use feeder, full stop. Whatever nutrition is in the worm when you buy it is what your skink gets.

Butterworm nutrition: rich, fatty, and palatable

Butterworms are, first and foremost, a fat delivery system, and that's not a knock — it's their whole value proposition. As-fed, they run high in fat (commonly cited somewhere around the high-20s to roughly 30%), with a moderate protein level. That fat is a concentrated, easily metabolized energy source, which is exactly what you want when you're trying to:

  • Tempt a picky or stressed eater into taking food at all.
  • Add weight to a skink that's thin, recovering from illness, or coming off brumation.
  • Reward and bond during hand-feeding, because their wriggle and scent reliably trigger a feeding response.

Their soft body is a real plus. There's no hard head capsule or tough shell to break down, so they're gentle on digestion and a good choice for a young skink, an older animal, or one recovering from a jaw or gut issue.

On calcium, butterworms are often praised, and here I want to be precise rather than repeat the usual overstatement. Butterworms do carry comparatively more calcium than many common feeders — that's a genuine, frequently noted trait. But "more than many feeders" is not "nutritionally complete" and it is not a free pass. They are still best treated as an occasional feeder, and dusting them with calcium powder before offering is still the wise default. Don't let the calcium reputation talk you into feeding them more often than their fat content allows — the fat is the limiting factor, every time.

The honest downsides of butterworms

I want you to use butterworms well, which means being clear-eyed about where they fall short:

  • High fat caps the frequency. This is the whole story. Fed too often, butterworms cause obesity and fatty-liver disease. They are a treat, not a staple, and no amount of calcium content changes that.
  • You can't gut-load them. Because they're dormant and don't feed, you can't pump extra nutrition into them the way you can a roach. What's in the worm is what your skink gets, plus a dusting.
  • Limited nutritional breadth. They're an energy-and-fat feeder, not a balanced one. Relying on them creates deficiencies over time.
  • Cost and availability. They tend to cost more than staple feeders, and supply can be seasonal and patchy because they can't be domestically cultured.
  • Lower enrichment value. They wriggle but don't run or climb, so they trigger less of the chase-and-hunt behavior that a moving roach provides. Minor, but worth noting if enrichment matters to you.

The summary on butterworms: a superb, palatable, fatty treat with a soft body and a decent calcium showing — best used deliberately and sparingly, never as the backbone of a diet.

Discoid roaches: the lean, breedable staple, profiled honestly

Discoid roaches — Blaberus discoidalis, sometimes called the "false death's head" roach — are a tropical species native to Central and South America. Note the scientific name: they are not Blaptica dubia (the dubia roach), a different species they're often confused with. Discoids are a popular feeder in their own right, and they're especially common with keepers in Florida, where dubia are restricted but discoids are permitted.

For a blue tongue skink, discoids check almost every box you want in a staple protein.

Discoid nutrition: high protein, moderate-to-low fat

Discoids are roughly 20–22% protein as-fed, with fat in the 6–10% range. That combination — solid protein, moderate-to-low fat — is precisely the profile of a good staple. It supports muscle and growth without the calorie overload that turns a feeder into a weight problem. Where butterworms are an energy bomb you ration, discoids are an everyday workhorse you can feed regularly to an active skink without worrying about obesity.

The calcium myth I have to correct

Here is the most important accuracy fix in this entire guide, because the claim is everywhere — including in the article this guide replaces.

Discoid roaches do NOT have a favorable 1:1 calcium-to-phosphorus ratio. That is a myth. Like nearly every feeder insect on earth, discoids are phosphorus-heavy — their calcium-to-phosphorus ratio is well below 1:1. (The rare genuine exceptions among common feeders are black soldier fly larvae, which actually are calcium-rich; almost everything else, discoids included, is not.)

Why does this matter? Because the dangerous mistake is to read "discoids have great Ca:P" and conclude you can skip calcium dusting. You can't. Calcium dusting is non-negotiable for any insect-based reptile diet. A diet that's chronically short on calcium relative to phosphorus drives metabolic bone disease (MBD) — soft, deformed bones, tremors, and eventually a crippled or dead animal. The Merck Veterinary Manual's reptile nutrition material is clear on this: dietary calcium-to-phosphorus imbalance is a primary driver of metabolic bone disease in captive reptiles, and supplementation is how you correct for the phosphorus-heavy reality of feeder insects. (See the Merck Veterinary Manual on reptile nutrition and metabolic bone disease.)

So let's be accurate about what discoids' real advantages are, because they're plenty good without the false claim:

  • High protein, moderate-to-low fat — the staple profile.
  • Low chitin, soft body — easy to digest, low impaction risk.
  • Breedable at home — a true sustainable staple, unlike butterworms.
  • Low odor, no biting, no climbing smooth walls — easy and clean to keep.

What they are not is a calcium shortcut. Dust them. Always.

Digestibility and the chitin question

The source article I'm replacing managed to contradict itself — calling discoids "low chitin" and easy to digest in one place, then "hard-bodied" and tough to chew in another. Let me settle it cleanly, because it matters for a skink.

Discoid roaches are relatively soft-bodied and low in chitin compared with crickets and mealworms. That's an advantage: less chitin means easier digestion and lower impaction risk, which is genuinely good for a blue tongue skink, especially a young or sensitive one. So on the question of "are they hard to digest?" the answer is no — they're one of the easier feeders.

The real variable isn't toughness, it's size. An adult discoid is a big roach — noticeably larger than a butterworm. A full-grown discoid offered to a small juvenile skink can be too much mouthful, not because it's hard but because it's large. The fix is the same rule that governs all feeders: match the feeder size to the skink (a feeder no wider than the space between the animal's eyes is the classic guideline), using smaller nymphs for smaller skinks and larger nymphs or adults for full-grown ones. Get the size right and the soft, low-chitin body works in your favor.

Discoids you can breed; butterworms you can't

This is the practical kicker that decides the staple role. Discoid roaches are a true colony feeder. Set up a warm bin (roughly 75–85°F, with hides and egg flats), feed them well, and they reproduce continuously — giving you a self-sustaining, cheap supply of staple protein you control. Butterworms, being irradiated and sterile, can never do this. If you want a feeder you can own and propagate rather than re-buy forever, the roach is the only option of the two, and it's a major point in its favor as a staple. (For the full colony build, I've written a complete discoid roach breeding playbook.)

When you want to start or top up a colony, or just buy well-started feeders sized for your skink, All Angles Creatures stocks healthy discoid roaches in a range of sizes for both colony seeding and direct feeding.

Butterworm vs. discoid roach: the head-to-head table

Here's the comparison laid out plainly. Treat the numbers as approximate, as-fed figures — actual values shift with source, diet, and life stage — but the relationships are what should drive your decisions, and those are reliable.

FactorButterworm (Chilecomadia moorei)Discoid roach (Blaberus discoidalis)
ProteinModerateHigh (~20–22%)
FatHigh (~high-20s to ~30%)Moderate–low (~6–10%)
CalciumComparatively high for a feeder — but still dustLow relative to phosphorus — must dust
Ca:P ratioBetter than most feeders, not "complete"Phosphorus-heavy (well under 1:1) — the 1:1 claim is a myth
Chitin / digestibilityVery soft, very easy to digestSoft, low chitin, easy to digest
PalatabilityExceptional — sweet scent, hard to resistGood — active movement triggers feeding
Care / storageRefrigerate 42–50°F; keeps weeks; no feedingWarm bin 75–85°F; ongoing care; lives indefinitely
Breedable at home?No — irradiated, sterile, buy-and-useYes — true breedable colony feeder
Cost / availabilityPricier, can be seasonalCheap, sustainable once colony established
Best roleOccasional treat — picky eaters, weight gainStaple protein — everyday feeding

The table tells the story at a glance: discoids win the staple role on protein, fat, breedability, and cost; butterworms win the treat role on fat, palatability, and convenience. Neither "wins" outright because they're not playing the same position.

Calcium, D3, and UVB: getting supplementation right

Since I've made such a point of dusting both feeders, let me actually explain the supplement side, because "dust with calcium" is the instruction everyone repeats and almost no one unpacks. Getting this right is what separates a skink with strong bones from one with metabolic bone disease, and it's the area where the most expensive feeder choice in the world won't save you if you skip it.

There are two distinct supplements doing two different jobs:

  • Plain calcium (calcium carbonate, no D3). This is the workhorse. It raises the calcium your skink ingests to offset the phosphorus-heavy reality of every feeder insect, butterworms and discoids included. If your skink has good UVB lighting, this is what you dust with most often, because the animal can make its own vitamin D3 from the UVB.
  • Calcium with D3. Vitamin D3 is the switch that lets the body actually absorb and use calcium. A skink getting strong UVB makes plenty of its own D3, so it needs little dietary D3 — and too much D3 is genuinely toxic (it causes harmful calcification of soft tissue). A skink with weak or no UVB relies on dietary D3, so it needs the D3 version more often. This is why you can't give a one-size-fits-all dusting schedule: it depends on your lighting.

The interaction that catches people out is UVB. Blue tongue skinks need a proper UVB source to process calcium at all. You can dust perfectly and still grow a skink with soft bones if the UVB bulb is dead, too weak, or so old it's stopped emitting useful output (UVB bulbs fade long before the visible light dies — replace them on the manufacturer's schedule, usually every 6–12 months). UVB plus calcium plus the right amount of D3 is a three-legged stool; knock out any leg and the whole thing falls.

A reasonable default for a UVB-equipped adult: dust feeders with plain calcium at most feedings, use a calcium-plus-D3 product lightly on a fraction of feedings, and add a reptile multivitamin sparingly (roughly once a week to once every couple of weeks) to cover trace nutrients and vitamin A. Juveniles, growing fast, lean toward more frequent calcium. When in doubt, a reptile vet who knows skinks can tailor this to your exact setup — and the Merck Veterinary Manual's reptile nutrition guidance is a solid, non-commercial reference on the calcium/phosphorus/D3 relationship behind all of it.

The practical mechanics are simple: put a pinch of supplement and your feeders in a cup or bag, give it a gentle swirl until the insect carries a light, even coat (think "lightly floured," not "caked"), and offer promptly before the powder falls off. For discoids you dust after gut-loading, so your skink gets both the nutrient-packed gut and the calcium coat. For butterworms you simply dust before offering, since gut-loading isn't possible.

Hydration and the role of moisture

Water is the quiet half of nutrition, and it interacts with these feeders more than you'd expect. Always keep a shallow, easy-to-access water dish in the enclosure — fresh daily. Beyond the dish, a meaningful amount of a skink's moisture comes from its food: the vegetables and fruit in the diet carry water, which is one more reason the plant side of the diet isn't optional.

Where the feeders come in: neither butterworms nor discoids is a hydration feeder (that's the job of something like a hornworm, which is mostly water). So if you're leaning hard on dry-stored butterworms or a roach-heavy stretch, make sure the produce and water dish are picking up the hydration slack. Watch the stool and skin — dry, hard stool and poor sheds are your early signals that moisture is short, and the fix is usually more leafy greens, a bit of fruit, and a check that the skink is actually drinking.

Building variety around the two feeders

Even with the staple/treat split sorted, neither feeder alone makes a complete diet — skinks are omnivores and thrive on rotation. Here's how I think about the wider menu so discoids and butterworms aren't carrying the whole load:

  • Other staple-class proteins. Lean options rotate well alongside discoids: appropriately sized dubia roaches (where legal), crickets, and the occasional bit of lean cooked meat or a high-quality, low-fat reptile/dog food in small amounts. Variety here covers amino-acid and micronutrient gaps.
  • Other treats. Superworms and waxworms are, like butterworms, fatty treats — useful in the same picky-eater/weight-gain role, used just as sparingly. Don't stack multiple fatty treats in the same week.
  • The plant foundation. This is the largest part of an adult's diet and where most of the variety should live: collard, mustard, dandelion, and turnip greens as the calcium-friendly base, plus squash, bell pepper, green beans, and carrot. Chop it so the skink can't pick out only its favorites.
  • Occasional fruit. Berries, mango, papaya, melon — small amounts, for vitamins and interest.

The mental model: greens and vegetables are the plate, a lean staple feeder (discoids) is the protein, and butterworms are dessert you serve once or twice a week. Build it that way and every feeding contributes to a balanced whole rather than leaning on any single item.

How to store and handle each feeder

Storage is where a lot of feeders die or spoil before they ever reach the skink. The two could not be more different here.

Storing butterworms

Butterworms are a refrigerator feeder, which is part of their convenience.

  • Keep them cold: about 42–50°F. A refrigerator's vegetable drawer is close to ideal. The cold holds them dormant, which is what gives them their multi-week shelf life.
  • Leave them in their original ventilated container with its dry bedding. Don't transfer them into something airtight.
  • Don't feed them. They're dormant and self-sufficient; food just invites mold and mess. This is the opposite of how you'd treat a live roach.
  • Keep them dry. Excess moisture means mold, and mold ruins the batch.
  • Cull the dead ones. Check periodically and pick out any worm that's gone dark, soft, or mushy before it fouls the rest.
  • Warm them before feeding. Take out what you need 10–15 minutes ahead so they warm up and start wriggling — a moving worm is far more enticing to a skink than a cold, stiff one.

Done right, a tub of butterworms keeps for several weeks, which makes them a low-effort thing to have on hand for treat day.

Storing discoid roaches

Discoids are the opposite — a living, warm-climate colony (or at minimum a holding bin) that needs ongoing, if light, care.

  • Warmth: 75–85°F. They're tropical. Too cold and they go sluggish and stop breeding.
  • A plastic bin or terrarium with a secure setup. Discoids cannot climb smooth vertical walls, so a smooth-sided bin contains the adults without a sealed lid — a real convenience and an important correction to anyone who tells you roaches will swarm out. What you do need to contain are the pinhead-sized nymphs, so cover any ventilation with fine metal mesh.
  • Egg flats or cardboard hides for surface area and security.
  • Feed them well — fresh vegetables, fruit, and a quality roach chow — and pull uneaten produce daily so it doesn't rot or mold.
  • Hydrate with water crystals or a sponge, never an open dish, which nymphs drown in.
  • Moderate humidity, good airflow. Damp-but-not-wet; stagnant wet bins grow mold and grain mites.

The trade-off is plain: butterworms are zero-maintenance but finite; discoids take real (if modest) care but renew themselves forever. That maintenance difference is exactly why butterworms read as "convenient treat" and discoids read as "infrastructure you build."

Safe handling, both feeders

  • Wash your hands before and after handling either feeder — basic hygiene against bacteria like Salmonella that any reptile-adjacent care involves.
  • Be gentle with butterworms. They bruise and rupture easily; don't squeeze or drop them. Tongs help.
  • Handle discoids firmly but calmly. They're flightless and don't bite, but they move fast — a feeding cup or tongs keeps things tidy.
  • Use feeding tongs if you'd rather not touch insects directly; it also keeps your fingers out of range of an enthusiastic skink's mouth.

Feeding schedules: putting both feeders to work

Here's how I actually use these two in a real skink's diet, by life stage. Remember the omnivore framework: greens and vegetables are the foundation, the feeder is the protein accent, and butterworms are a treat layered on top — never the base.

Juveniles (hatchling to roughly a year)

Young skinks grow fast and need protein often.

  • Frequency: Feed daily or every other day.
  • Protein share: Higher than for adults — animal matter can be roughly half the diet early on, tapering as they grow.
  • Staple feeder: Appropriately sized discoid nymphs, dusted with calcium (with D3 per your UVB setup) at nearly every feeding. Size the nymph to the skink — small skink, small nymph.
  • Vegetables: Around 40% of intake even at this age — start the greens habit early so it's normal by adulthood.
  • Butterworms: A treat, not a routine. One to two times a week, one to two worms as a reward or to entice a reluctant baby. Don't let a juvenile fill up on fat.

Adults (roughly a year and up)

Adults have slower metabolisms and a plant-forward diet.

  • Frequency: Two to three times per week is plenty.
  • Protein share: The smaller portion now; vegetables climb to 50–60% of the diet.
  • Staple feeder: Discoid roaches (larger nymphs or adults, sized to the skink), dusted with calcium. A few per feeding, alongside the vegetable mix.
  • Butterworms: Still a treat — once or twice a week, one to three worms for an adult, and dialed back further if the skink is carrying extra weight. They're also your go-to tool to coax an adult that's gone off its food.

The picky-eater and weight-gain playbook

This is where butterworms genuinely shine and earn their place in your fridge:

  • Off its food? A wriggling, sweet-smelling butterworm offered by tongs will tempt most reluctant skinks. Once it's eating, transition back toward the leaner staple.
  • Underweight or recovering? Their concentrated fat is ideal short-term fuel for a thin animal, a skink coming out of brumation, or one bouncing back from illness — used temporarily and watched.
  • Mixing a refused vegetable? Some keepers crush a butterworm over chopped greens to make the whole bowl smell appealing, getting a stubborn skink to eat its plants. Use sparingly given the fat.

Once the skink is eating well and at a healthy weight, pull the butterworms back to treat frequency. They're a tool for a problem, not a permanent fixture.

Common feeding mistakes that hurt skinks

Most diet problems I see come down to a handful of avoidable errors. Watch for these:

Feeding the treat like a staple

The number-one mistake with these two feeders specifically: making butterworms (or any fatty feeder) the everyday protein. The skink loves them, eats eagerly, and you feel like a great keeper — right up until it's obese with a fatty liver. Keep butterworms to treat frequency and let leaner discoids carry the staple load.

Skipping calcium because of a Ca:P myth

The second mistake, and the reason I hammered the point earlier: believing discoids (or butterworms) have such great calcium that you can skip dusting. You can't. Feeder insects are phosphorus-heavy; dusting with calcium is what prevents metabolic bone disease. Dust at feedings as your skink's age and UVB setup require.

A monotonous diet

Even feeding discoids perfectly, an all-discoid diet is a mistake. Skinks are omnivores — they need the greens, the vegetable variety, the occasional fruit and protein rotation. Variety covers the micronutrient gaps any single feeder leaves. Rotate.

Neglecting gut-loading

This one applies to the roach, not the worm. Gut-load discoids for 24–48 hours before feeding — feed the roaches quality produce and chow so they're nutrient-packed when your skink eats them. (You can't gut-load butterworms; they're dormant.) Skipping this turns a good feeder into an empty one.

Wrong feeder size

Too big risks choking and impaction; too small isn't worth the skink's effort. Keep feeders no wider than the space between the skink's eyes. This matters more with discoids, since an adult is a big roach.

Toxic and wild-caught foods

Never feed avocado, onion, garlic, or rhubarb. Never feed wild-caught insects — they may carry pesticides or parasites. Source feeders from reputable suppliers only.

A stressful feeding environment

A skink won't eat well under bright light, loud noise, or constant handling. Offer food in a calm, quiet setting and give the animal space to eat. A stressed skink that "won't eat butterworms" sometimes just needs the room to settle.

Monitoring your skink through its diet

The diet is working or it isn't, and your skink will tell you if you watch. I check four things regularly:

  • Body condition. A healthy blue tongue is plump but not bloated — no fat bulging at the limb pits or tail base. Visible fat deposits there are the early warning that the fatty feeders (butterworms) have crept up too high. Weigh periodically and track the trend.
  • Appetite and energy. A bright, alert, hungry skink is a well-fed skink. Persistent lethargy or food refusal warrants attention — and is, incidentally, exactly when a butterworm earns its keep as an appetite-starter.
  • Stool. Firm and well-formed is the goal. Loose or greasy stool often means too much fatty feeder (dial back the butterworms); very dry, hard stool can mean dehydration or not enough vegetables.
  • Skin and sheds. Clean, complete sheds and good color reflect adequate hydration and vitamins (notably A and D3). Poor sheds or dull skin point to a supplementation or hydration gap.

Keeping a simple feeding journal — what you offered, what was eaten, weight every few weeks — turns all of this from guesswork into a pattern you can actually manage. It's the difference between catching a slow weight gain at month two versus discovering an obese skink at month eight.

The verdict: staple vs. treat, settled

After all the detail, the call is clean and I'll give it to you straight:

Discoid roaches are the better staple protein. They're high-protein and moderate-to-low fat, soft-bodied and low-chitin (easy to digest, low impaction risk), and — crucially — you can breed them at home for a cheap, endless, sustainable supply. They make the perfect everyday backbone of the animal-protein side of a blue tongue skink's diet. Just remember to size them to your skink, gut-load them, and dust with calcium every time, because the "perfect 1:1 Ca:P" reputation is a myth and they're phosphorus-heavy like nearly all feeders.

Butterworms are the better occasional treat. They're high-fat, exceptionally palatable, and soft-bodied, which makes them the ideal tool for tempting a picky eater, hand-feeding for a bond, or adding weight to a thin or recovering skink. They carry comparatively more calcium than many feeders, but the fat content keeps them firmly in treat territory — once or twice a week, a worm or two — and being irradiated and sterile, they're always a buy-and-use feeder, never a colony.

The real answer to "which one?" is both, used correctly: build the diet on discoid roaches and leafy greens, keep butterworms in the fridge for treat day and trouble-shooting, and rotate in other feeders, vegetables, and the occasional fruit for variety. Do that and you've got a balanced, sustainable feeding routine that keeps a blue tongue skink lean, active, and healthy for the long haul.

And whenever you're ready to stop re-buying feeders and start owning your staple, a discoid colony is the move — it's genuinely the most boring, low-effort infrastructure in my animal room, which for a feeder is exactly the goal.

Still weighing feeders? See my head-to-head on discoid roaches vs. giant mealworms for blue tongue skinks, my guide to how many discoid roaches to feed your reptile, or browse the full exotic animal care library for the rest of the feeders.