Discoid Roaches vs. Giant Mealworms for Blue Tongue Skinks: A Keeper's Head-to-Head

I've kept feeder colonies and fed a lot of reptiles over the years, and the question I get most often from blue tongue skink keepers is some version of: "discoid roaches or giant mealworms?" It sounds like a small decision. It isn't. The feeder you build a skink's protein around shapes its weight, its bone health, and its lifespan, and these two feeders sit at opposite ends of the quality spectrum. One is arguably the best staple insect you can offer a skink. The other is a fatty treat that too many people accidentally turn into a diet.

This is the full head-to-head. I'll cover what a blue tongue skink actually needs from its diet, then put discoid roaches (Blaberus discoidalis) and giant mealworms (Tenebrio molitor) side by side on every axis that matters — protein, fat, the calcium-to-phosphorus problem, digestibility and impaction risk, cost and availability, breeding and maintenance, feeding behavior and enrichment, the real risks of each, and sustainability. There's a comparison table in the middle that's the heart of the whole thing. And I'll give you a clear verdict instead of the wishy-washy "it depends" you usually get.

One housekeeping note up front, because the internet is full of bad information on this: I'm going to correct a few myths along the way, including some that the original version of this article got wrong. The most important one is what a "giant mealworm" even is, so let's start there before we get into nutrition.

What a giant mealworm actually is (and what it isn't)

A giant mealworm is not a separate species. It is an ordinary mealworm — the larva of the yellow mealworm beetle, Tenebrio molitor — that has been treated with a juvenile hormone analog. That hormone keeps the larva in its growing, feeding stage and prevents it from pupating into a beetle. Because it never gets the signal to stop growing and metamorphose, it keeps eating and keeps getting bigger, ending up noticeably larger than a standard mealworm. That's the entire trick. "Giant" is a chemically extended regular mealworm, not a giant breed of anything.

This matters for two reasons. First, the hormone treatment is the reason giant mealworms generally won't pupate or breed normally — I'll come back to that under breeding, because it kills the "I'll just breed my own" plan. Second, and this is the correction I most want to nail down: giant mealworms are not superworms.

Superworms are Zophobas morio, a genuinely different and larger species of darkling beetle larva. They reach their size naturally, without hormone treatment, and they pupate and breed on their own (under the right conditions). You'll see careless sources — including the article this guide replaces — call giant mealworms "Zophobas morio." That is flat-out wrong. Zophobas morio is the superworm. The giant mealworm is hormone-treated Tenebrio molitor. If you take nothing else from this section, take that: giant mealworm = hormone-treated Tenebrio molitor; superworm = Zophobas morio; they are not the same animal.

Why be this pedantic? Because the species determines the nutrition, the breeding behavior, and the risks, and if you're shopping or reading care advice based on the wrong identity, every downstream decision is built on sand.

What blue tongue skinks actually need to eat

Before comparing feeders, you have to know the target. Blue tongue skinks (genus Tiliqua) are stout, docile, ground-dwelling lizards from Australia, Indonesia, and New Guinea, and the single most important fact about their diet is that they are omnivores — not insectivores, not herbivores. In the wild they forage opportunistically across insects, snails, worms, carrion, small animals, fallen fruit, flowers, and a lot of plant matter. A captive diet that ignores either side of that — all bugs or all salad — will eventually make them sick.

The working ratio most experienced keepers use is roughly 50% animal protein and 50% plant matter for adults, with juveniles tilted a bit more toward protein to fuel growth, and very old or sedentary adults often tilted a bit more toward greens to control weight. The plant half should be mostly dark leafy greens and vegetables — collard, dandelion, mustard and turnip greens, squash, bell pepper, green beans — with fruit as an occasional sweet extra (berries, melon, a little banana), not a staple. The protein half is where feeder insects, lean cooked meats, eggs, and high-quality wet dog/cat food or a formulated skink diet come in.

A few dietary rules drive everything that follows:

• ◆Obesity is the chronic threat. Skinks are built to take advantage of feast conditions and they will happily eat themselves into a fatty, short-lived animal. Captive skinks are far more often overweight than underweight. This is why a feeder's fat content is not a footnote — it's a primary screening criterion. Hold this thought when we get to giant mealworms.
• ◆Calcium and the Ca:P ratio rule bone health. Reptiles need more calcium than phosphorus in their overall diet. Feed them phosphorus-heavy items without correcting for it and you march them toward metabolic bone disease (MBD) — soft, deformed bones, tremors, and worse. The Merck Veterinary Manual's overview of metabolic bone disease in reptiles is the authoritative non-commercial read on why dietary calcium, phosphorus, and vitamin D3 balance is non-negotiable. Nearly every feeder insect fails this ratio on its own, which is why dusting exists.
• ◆Avoid the calcium-blockers on the plant side too. Greens very high in oxalates (spinach, rhubarb, chard) bind calcium and work against you. Keep them out of the rotation or minimal.
• ◆Variety beats any single perfect feeder. No one insect is a complete diet. The goal isn't to crown one bug king forever; it's to choose the right staple to build a rotation around and the right treats to mix in occasionally.

With the target defined, let's profile each contender honestly.

Nutritional profile: discoid roaches

Discoid roaches (Blaberus discoidalis) are a tropical, soft-bodied roach from Central and South America, and they've earned their reputation as a premium feeder for omnivores like skinks. Here's the honest breakdown.

Protein: High. Discoids land around 20% as-fed, and you'll see figures up toward the low-to-mid 20s on a dry-weight basis depending on diet and life stage. That's a strong, usable protein level for muscle, growth, and tissue repair, with a reasonably balanced amino acid profile. For a skink's protein half, this is exactly the range you want — substantial but not so extreme it crowds out the plant side of the diet.

Fat: Moderate, roughly 6–7% as-fed. This is the quiet superpower. Moderate fat means you can feed discoids regularly without driving the obesity that fattier feeders cause. They deliver protein-forward nutrition rather than a calorie bomb.

Moisture: High, around 60–65%. That contributes to hydration, which is a minor but real plus, especially for skinks that don't drink enthusiastically from a bowl.

Calcium-to-phosphorus ratio: Here's where I have to correct the record, including the article this one replaces. Discoid roaches do NOT have a "balanced 1:1" or "favorable" Ca:P ratio. That is a myth that gets repeated constantly. Like almost every feeder insect, discoids are phosphorus-heavy — they carry more phosphorus than calcium — which means on their own they tilt a skink toward calcium deficiency, not away from it. The fix is the same as for nearly all feeders: dust them with a calcium supplement before feeding, and gut-load them well. Their genuine advantages are high protein, moderate fat, and low chitin — not their minerals. Don't let anyone sell you discoids on a fake Ca:P claim; sell yourself on the protein, the low fat, and the digestibility, and then dust them like you would anything else.

Chitin and digestibility: Excellent. Discoids have a soft, low-chitin exoskeleton. Chitin is the tough structural material in insect shells; the less of it, the easier the feeder is to break down and the lower the impaction risk. Discoids are about as gentle on a reptile's gut as a substantial insect gets, which is a big part of why they're safe for juveniles and sensitive animals.

Micronutrients: They carry trace B-complex vitamins and minerals like potassium and magnesium, and — critically — they gut-load extremely well. What the roach eats becomes part of what your skink eats. Feed the colony calcium-rich greens and a quality dry diet for 24–48 hours before offering them, and you meaningfully upgrade their value at the moment of feeding.

The short version on discoids: high protein, low-moderate fat, soft body, easy to digest, gut-loads beautifully, needs calcium dusting like everything else. That's a staple-grade feeder.

Nutritional profile: giant mealworms

Giant mealworms (hormone-treated Tenebrio molitor) are popular for one honest reason — they're cheap, large, and everywhere — but their nutrition tells you to be careful.

Protein: Moderate, roughly 18–20%. Slightly lower than discoids and, just as importantly, paired with a less favorable amino-acid balance and a tougher delivery package (more on that under digestibility). It's real protein, but it's not the cleanest protein.

Fat: High — about 12–14%, sometimes higher. This is the headline problem. That's roughly double a discoid's fat. For an animal whose number-one chronic health risk is obesity, a high-fat staple is exactly backwards. Fat is useful for a thin, recovering, or breeding animal in small doses, but as a routine feeder it pushes skinks toward weight gain and fatty liver disease.

Moisture: Around 60–65%, similar to discoids — fine, but it also means the high fat is concentrated in the dry fraction.

Calcium-to-phosphorus ratio: Poor — and worse than discoids. Giant mealworms are heavily phosphorus-skewed, on the order of 1:13 or worse (far more phosphorus than calcium). Left uncorrected that's a fast track to MBD. You can dust and gut-load to compensate, but you're fighting a steeper hill than you are with discoids, and the hard exoskeleton (next point) makes even getting the calcium absorbed harder.

Chitin and digestibility: This is the other big mark against them. Giant mealworms have a thick, chitin-rich exoskeleton. That hard skin is harder to digest and, fed in quantity, can contribute to gut impaction — a genuine danger for juveniles and smaller skinks, and the reason vets caution against making them a staple. Their elongated, wriggly bodies can also be awkward for some skinks to swallow.

Micronutrients: Modest, and the chitin barrier blunts how much your skink actually absorbs.

The short version on giant mealworms: cheap and big, moderate protein, but high fat, a worse Ca:P ratio, a hard impaction-risky shell, and the hormone-treatment baggage. That's a treat, not a foundation.

The head-to-head table

This is the comparison everyone actually came for. Treat the numbers as approximate, as-fed figures — real values swing with diet, life stage, and supplier — but the relationships between the two are reliable, and the relationships are what should drive your decision.

The table makes the verdict almost write itself, but each row deserves a sentence of context, because "cheaper" and "everywhere" are the two things that tempt people into the wrong choice.

Protein, read correctly

On paper the protein gap looks small — roughly 20% versus 18–20%. But two things widen it in practice. First, the amino acid balance in discoids is more complete and usable for a reptile. Second, bioavailability: the discoid's soft body means more of that protein is actually digested and absorbed, while the mealworm's hard chitinous shell locks some of its nutrition behind material the skink can't efficiently break down. So even where the headline percentages are close, the discoid delivers more usable protein per feeder. For an animal that needs solid protein without a fat penalty, that's a meaningful edge.

The calcium-to-phosphorus problem, honestly

Let me restate the rule because it's the one most likely to hurt your animal if you get it wrong. Reptiles need a dietary Ca:P ratio of roughly 1.5:1 to 2:1 — more calcium than phosphorus. Both of these feeders fail that on their own. Neither discoids nor giant mealworms have good calcium numbers; both are phosphorus-heavy and both require calcium dusting. The difference is degree: discoids are moderately phosphorus-heavy, giant mealworms are dramatically so (around 1:13).

That means:

• ◆Dust calcium on every feeding of either insect. A plain calcium powder (calcium carbonate) for routine feedings, and a calcium-with-D3 product on the schedule your setup calls for (less D3 needed if your skink gets good UVB; more relevant if it doesn't). The Merck Veterinary Manual's reptile-nutrition material is the reference I'd point any keeper to for understanding the calcium/phosphorus/D3 triangle and why MBD develops when it's off.
• ◆Gut-load before feeding. Calcium-rich greens and a quality dry diet in the feeder for 24–48 hours raises what your skink actually receives. Discoids gut-load especially well thanks to their appetite and soft body.
• ◆Don't believe the "1:1 discoid" claim that's floating around (and was in the source article). It's wrong, and believing it leads people to skip dusting, which is exactly how MBD sneaks in.

The takeaway: the Ca:P axis isn't a reason to pick discoids over giant mealworms by itself — you're dusting both. But the giant mealworm's far worse ratio, combined with its hard shell limiting calcium absorption, stacks one more disadvantage onto an already-treat-tier feeder.

Digestibility, chitin, and impaction risk

This is the axis where the two feeders genuinely diverge for skink health, and it's a big one.

Chitin is the tough polymer that makes up an insect's exoskeleton. A little is fine — it acts like fiber. A lot, especially in hard-shelled feeders eaten in quantity, is a problem: it's poorly digestible and can accumulate, contributing to impaction, a potentially serious blockage of the gut. Juveniles and smaller skinks are most vulnerable because their digestive systems are less robust and the relative size of the shell is larger.

Discoid roaches are soft-bodied and low in chitin. They break down easily, they're forgiving of younger animals, and they carry a low impaction risk. You can feed them regularly without lying awake about it.

Giant mealworms are the opposite: a thick, chitin-rich exoskeleton wrapped around that high-fat body. Fed sparingly to a healthy adult skink, an occasional one is fine. Fed in quantity, or to a juvenile, the hard shells are a real impaction hazard. This single trait is the strongest husbandry argument for keeping giant mealworms occasional. Add the difficulty some skinks have swallowing the long, wriggling bodies, and you've got a feeder that's harder on both ends of the process.

If you do offer giant mealworms, two mitigations help: offer them to adults rather than juveniles, and offer them freshly molted when you can (a recently shed, paler mealworm has a softer cuticle for a short window). Neither changes the fat or the Ca:P math — they only soften the impaction edge.

Availability and cost: where the temptation lives

Let me be straight about the one category where giant mealworms genuinely win, because it's why so many people end up over-relying on them.

Availability. Giant mealworms are everywhere — every pet store, every reptile expo, every online supplier. Because they're just enlarged standard mealworms, supply is deep and reliable. Discoids are more specialized: they're carried by exotic-feeder shops and, more dependably, online suppliers, and because they're sometimes in lower demand than dubia roaches, they can occasionally be harder to find locally. Discoids also breed slowly, so suppliers (and you) need to plan ahead.

A real-world legality note on discoids: they're legal in most U.S. states and are notably popular in Florida, where dubia roaches are restricted — discoids are an accepted alternative there. But regulations on non-native species vary, so confirm your state and local rules before ordering. A reliable non-commercial reference for feeder-insect and invasive-species information is the University of Florida's entomology and nematology department.

Cost. Giant mealworms are cheap: $10–15 buys several hundred worms, and they store easily in the fridge with minimal care. Discoids cost more per feeder — roughly $15–25 for 50–100 — plus the heat-pack shipping live roaches require. On pure dollars-per-bug, mealworms win going away.

Here's the trap, though: cost-per-feeder is the wrong metric. The right metric is cost-per-healthy-year-of-skink. A cheap feeder that drives obesity, MBD risk, and impaction isn't cheap; it's expensive in vet bills and shortened lifespan. Discoids cost more up front and pay it back in a leaner, sounder animal — and if you breed them (next section), the per-feeder cost collapses over time. Don't let the sticker price make a nutrition decision for you.

Breeding and maintenance

If you want to control quality and cost long-term, breeding your own feeders is the move — and this is another category where the two feeders aren't even close.

Discoid roaches breed well at home. They're live-bearers: females develop the egg case (ootheca) internally and give birth to live nymphs, so you never lose a clutch to a dried-out egg case. Set them up in a dark, ventilated, opaque bin with vertical egg flats, hold the warm zone at 85–90°F (they tolerate up to the mid-90s) and humidity around 60–70%, feed them produce plus a dry protein diet, and a colony produces continuously with overlapping generations. The catch is patience — discoids mature in roughly 4–6 months and ramp slower than dubia — but once established, a colony quietly supplies feeders for years. A side benefit worth naming: discoids can't climb smooth vertical walls, so a smooth-sided bin contains adults without elaborate barriers. (They can grip rough surfaces and screen, and pinhead nymphs slip through coarse vents, so fine mesh on openings is still smart — but the "they climb smooth walls and escape everywhere" claim is wrong.) If you want the full colony build, I've written a dedicated discoid roach breeding playbook. And when you need to seed or top up a colony, All Angles Creatures stocks healthy, well-started discoid roaches sized for both breeding and direct feeding.

Giant mealworms essentially can't be bred — and this is a direct consequence of what they are. Remember: they're standard mealworms dosed with a juvenile hormone analog that suppresses pupation. That treatment is the whole reason they grow so large, and it's also the reason they generally won't pupate into beetles and reproduce. They just sit in their feeding stage until used. If you want to breed mealworms, you have to start with untreated, standard mealworms, let them pupate into darkling beetles, and let the beetles lay eggs — a slow, months-long cycle that produces normal-sized mealworms, not giants. So the "I'll just breed my own giant mealworms to save money" plan doesn't exist. With giant mealworms you are always buying, forever.

On day-to-day maintenance, giant mealworms are genuinely lower-effort to store — a tub of bran in the fridge slows them down and they keep for weeks. Discoids need an actual warm, humid colony if you're keeping them alive long-term. So if you only want to buy small batches and store them, mealworms are simpler. But "simpler to store" and "better for your skink" are different questions, and only one of them should decide your staple.

Feeding behavior and enrichment

Skinks are intelligent, observant foragers, and how a feeder behaves affects the quality of the feeding experience — which is real enrichment, not a throwaway concern.

Discoid roaches move at a moderate, deliberate pace and will burrow into substrate or hide under cover when they can. In a bioactive or naturalistic enclosure that triggers genuine foraging and digging behavior — the skink works to find and catch them, which is mentally and physically good for the animal. The downside is the flip side of the same trait: a roach that hides too well can go uneaten and lurk in the enclosure, so in heavily planted setups it's worth feeding in a dish or supervising.

Giant mealworms are wriggly and stay on the surface — they don't burrow effectively — so they're highly visible and easy for a skink to spot and grab. That makes them useful for a finicky eater, a sick animal you need to tempt, or feeding in a dish where you want to see exactly what got eaten. The flip side is they offer less of a foraging challenge, and on smooth flooring a fast-wriggling worm can occasionally frustrate a less agile skink. They can also nip — use feeding tongs rather than fingers, both to avoid the bite and to control portions.

Neither behavior is a deciding factor on its own, but it nudges use: discoids suit naturalistic, enrichment-focused feeding; giant mealworms suit targeted, see-it-get-eaten dish feeding for treats or appetite-tempting.

Risks and precautions, side by side

Every feeder has failure modes. Here's what to actually watch for with each.

Discoid roaches

• ◆Overfeeding. They're palatable and easy to eat, so it's easy to offer too many and fatten a skink even on a lean feeder. Portion to the animal's size and condition; protein is half the diet, not all of it.
• ◆Containment of nymphs. Adults can't climb smooth walls, but pinhead nymphs can slip through coarse ventilation. Fine metal mesh on vents keeps every life stage contained. (Don't believe sources claiming adults scale glass — they don't.)
• ◆Allergies/hygiene. A small number of people react to roach frass or shed exoskeletons. Wash hands, and if you're sensitive, gloves and good colony ventilation help.

Giant mealworms

• ◆Impaction from chitin. The big one. Hard shells fed in quantity, or to juveniles, risk gut blockage. Keep them occasional and aim them at adults.
• ◆Obesity from fat. ~12–14% fat adds up fast. Routine feeding pushes skinks toward overweight and fatty liver. Treat-only frequency is the guardrail.
• ◆The hormone treatment. They're produced with a juvenile hormone analog to reach size. Long-term effects of feeding hormone-treated insects aren't well studied, and many keepers prefer caution — another reason to keep them an occasional item rather than a daily staple. (If you specifically want a large worm without hormone treatment, that's the lane superworms — Zophobas morio — occupy, though superworms bring their own high-fat, hard-shell cautions.)
• ◆Biting. They can nip a skink's mouth or your fingers. Tongs solve it.

Read the two lists together and the pattern is obvious: the discoid's risks are mostly handling and overfeeding problems you control with simple habits; the giant mealworm's risks are intrinsic to the feeder — its fat, its shell, its production method — and you can only manage them by feeding it rarely.

Sizing the feeder to the skink

A feeder that's the wrong size is a problem regardless of how good its nutrition is, and the two contenders behave differently here.

The universal reptile rule of thumb is to keep prey no wider than the space between the animal's eyes — for skinks, no wider than the gap across the head, and short enough to swallow without a struggle. Adult blue tongue skinks are big lizards with wide mouths, so an adult discoid roach (up to about two inches) is a comfortable, single-piece meal for a grown skink. That's actually one of the discoid's quiet advantages: a single large feeder does the work of many small ones, so feeding is fast and you're not chasing a dozen tiny bugs around the enclosure.

For juvenile skinks, that same large adult discoid is too much — but discoid colonies produce every size from pinhead nymphs up, so you simply pick smaller nymphs sized to the young animal. This is another argument for keeping a colony rather than buying one size: you always have the right size on hand as the skink grows.

Giant mealworms are sold at one large size, which is part of their appeal for adult skinks and part of the problem for juveniles. A long, hard-shelled giant mealworm is exactly the wrong shape and texture for a young skink's gut — the impaction risk I covered earlier is at its worst here. If you're feeding a juvenile and reaching for worms at all, standard (non-giant) mealworms or, better, appropriately sized soft feeders are the safer call, and giant mealworms should wait until the animal is a robust adult.

Gut-loading: getting more out of either feeder

Whatever you feed, gut-loading is the lever that turns an average feeder into a good one, and it partly closes the gap on the mineral problem both insects share.

Gut-loading means feeding the feeder a nutrient-rich diet for 24–48 hours before it goes to your skink, so the insect's gut is full of good nutrition at the moment it's eaten. A working gut-load mix is a calcium-rich, moisture-bearing produce plus a quality dry diet: collard and dandelion greens, squash, carrot, sweet potato, a little bell pepper, alongside a commercial gut-load or roach chow. The calcium-rich greens matter because they help offset the phosphorus skew in both feeders — though gut-loading supplements dusting, it does not replace it.

Discoids gut-load especially well. They eat enthusiastically, their soft bodies pass that nutrition along efficiently, and they hold a full gut without trouble. Giant mealworms can be gut-loaded too — many keepers bump them onto a calcium-rich substrate and fresh greens before feeding specifically to soften their terrible Ca:P ratio — but their hard shell limits how much of that gets absorbed by your skink, so you're getting less return on the same effort. The same protocol, in other words, pays off more on the discoid.

The practical habit: gut-load, then dust, then feed promptly. Pull the feeders after their 24–48 hour load, toss them in calcium powder (with D3 on your schedule), and offer them right away so the nutrition is at peak.

Feeding frequency, portions, and weight management

Because obesity is the chief chronic risk for captive skinks, portioning is where a lot of well-meaning keepers go wrong — and where the feeder choice has teeth.

A rough framework I use, adjusted to the individual animal's body condition:

• ◆Juveniles (growing): feed daily or near-daily, tilted toward protein to fuel growth — appropriately sized discoid nymphs and other quality proteins, alongside finely chopped greens. Keep giant mealworms out at this stage; the impaction and fat risks are highest in young animals.
• ◆Sub-adults: feed every day or every other day, easing toward the adult 50/50 protein-to-plant balance as they grow.
• ◆Adults: feed every 2–3 days, with the diet roughly half plant matter and half protein. Discoids slot into the protein half as a regular item; an occasional giant mealworm can ride along as a treat for variety.
• ◆Older or sedentary adults: tilt further toward greens and watch weight closely; reduce fatty extras like giant mealworms to near zero.

Watch the body condition, not just the calendar. A healthy skink is solid and rounded but not bulging; you should not see rolls of fat around the limbs or a tail that's ballooned. If the animal is gaining, cut the fatty feeders first — and giant mealworms are the first thing to go. This is the single clearest place the feeder choice shows up in practice: a skink fattening on a discoid-and-greens diet is rare; a skink fattening on giant mealworms as a staple is common.

And know the warning signs of the two diseases each feeder's weakness drives. For obesity/fatty liver: lethargy, a swollen body, reluctance to move, poor appetite. For metabolic bone disease (MBD) from chronic calcium shortfall: tremors or twitching, soft or deformed jaw and limbs, difficulty walking or lifting the body, swollen limbs. MBD in particular is largely preventable with proper Ca:P management — dusting, gut-loading, and UVB — and the Merck Veterinary Manual's reptile-nutrition material lays out why. If you see these signs, a reptile vet, not a forum, is the next step.

Where each fits in the wider rotation

Neither feeder is the whole answer, and it helps to place them in the full lineup a skink keeper draws from.

A blue tongue skink's protein half should rotate across several sources: discoids (and other feeder roaches) as the insect staple, plus lean cooked meats, cooked egg, snails, and a high-quality wet cat/dog food or formulated skink diet for convenience and consistency. Within the insect options, think of feeders in tiers:

• ◆Staple insects (regular use): discoid roaches, dubia roaches, and similar high-protein, moderate-fat, low-chitin feeders. These are your everyday protein bugs.
• ◆Treat insects (occasional): giant mealworms, superworms, waxworms, butterworms — higher fat, harder shells, or both. Great for variety and tempting, bad as a foundation.
• ◆Hydration/variety insects: softer, high-moisture options used for specific purposes.

Giant mealworms sit firmly in the treat tier alongside superworms and waxworms — all three are feeders you reach for occasionally, not daily. Discoids sit in the staple tier. Seen this way, the "discoid vs. giant mealworm" question is slightly miscast: they're not really competing for the same job. One is meant to be a backbone; the other is meant to be a garnish. The mistake people make is promoting the garnish to backbone because it's cheap and easy to find.

A note on the "expert consensus"

If you read around — vets, reptile nutritionists, experienced keepers — the consensus on these two is remarkably consistent, and it lines up with the nutrition. Discoids get recommended as a staple for omnivorous reptiles like skinks on the strength of their protein-to-fat ratio, soft digestible bodies, low impaction risk, and how well they gut-load. The main caveats raised are practical: their larger size needs portioning for juveniles, and they cost more.

Giant mealworms get a far more cautious reception. The recurring warnings are exactly the three intrinsic weaknesses: too much fat to be a staple (obesity), a chitin-heavy shell (digestive strain and impaction, especially in young skinks), and the need for diligent calcium supplementation against their poor Ca:P ratio. The kinder takes frame them as a fine occasional feeder when gut-loaded and fed in moderation. Almost no one who looks at the nutrition recommends them as a primary protein source — which is the same place this guide lands.

Sustainability

For keepers who weigh the environmental side, discoids again come out ahead, and it's worth a paragraph because it's a real difference.

Discoid roaches are remarkably resource-efficient: they need little space, water, or feed to produce a lot of feeders, their frass is a nutrient-rich, compostable fertilizer, and their colonies are low-odor and low-methane compared with many farmed insects. You can run a productive colony in a bin on a shelf.

Giant mealworm production carries more overhead: mealworms are typically raised on grain and bran substrate, which ties their footprint to grain agriculture, and the giant version specifically requires the hormone-treatment step to reach size — an added input that standard insect farming doesn't need. Their frass is compostable but less nutrient-dense than roach frass. Both feeders are far more sustainable than vertebrate prey, but discoids are the lighter-footprint option, and if you breed your own, your supply chain is essentially a bin in your house.

The verdict

After all of it, the recommendation is clear and I won't hedge it:

Discoid roaches are the better staple feeder for blue tongue skinks. Giant mealworms are an occasional treat — never the foundation of the diet.

The reasoning, stacked up:

• ◆Discoids win on the nutrition that matters for skinks: comparable-to-better usable protein, half the fat, soft low-chitin bodies that digest easily and don't risk impaction, and excellent gut-loading. Their only real nutritional caveat — phosphorus-heavy minerals — is shared by virtually every feeder and is solved with calcium dusting.
• ◆Giant mealworms lose on exactly the things a skink is most vulnerable to: high fat (obesity), a far worse Ca:P ratio (MBD), and a hard chitinous shell (impaction). Add the hormone-treatment question marks and the fact that you can't breed them, and they're a convenience feeder, not a quality one.
• ◆Giant mealworms genuinely win on cost and availability — but those are your conveniences, not your skink's health, and cost-per-feeder is the wrong way to price a diet.

So here's how I'd actually run it. Build the protein half of your skink's omnivore diet around discoids as the regular insect staple (sized to the animal, dusted with calcium, gut-loaded before feeding), alongside the other quality proteins skinks take — lean cooked meats, eggs, a good formulated diet — and the full plant half of greens and occasional fruit. Keep giant mealworms in the treat drawer: a few now and then for an adult, for variety or to tempt a reluctant eater, offered with tongs and never as the meal itself. Best of all, if you set up a discoid colony, your staple becomes something you produce at home for pennies, while the "cheap" mealworm stays a perpetual purchase.

That's the whole head-to-head. Pick the feeder that fits the animal's biology, not your checkout total, and a blue tongue skink will reward you with a long, lean, sound-boned life.

Building a skink's full feeder rotation? Compare butterworms vs. discoid roaches for blue tongue skinks, dial in portions with how many discoid roaches to feed your reptile daily, or browse the full exotic-animal care library for the rest of the feeders worth knowing.