Discoid Roaches vs. Mealworms for Blue Tongue Skinks: Which Is the Better Feeder?
If you keep a blue tongue skink, you'll eventually face the feeder aisle question: discoid roaches or mealworms? Both are easy to get, both are eaten readily, and both show up in starter kits and care sheets as if they're interchangeable. They aren't. One makes a genuinely good staple protein for an omnivorous, obesity-prone lizard; the other is best kept to an occasional treat. Here's the honest comparison, and the verdict.
What a blue tongue skink actually needs
Blue tongue skinks (the Tiliqua genus, native to Australia and nearby islands) are omnivores, not insectivores. In captivity a balanced diet runs roughly 50% animal protein, 40% vegetables and leafy greens, and 10% fruit. The protein portion is where feeder insects come in, and the qualities that matter most for a skink are:
- Adequate but not excessive protein for muscle and growth.
- Moderate fat — skinks have a slow metabolism and put on weight easily, so a low-fat protein source matters more than most keepers realize.
- Digestibility — a soft, low-chitin body is easier on the gut and lowers impaction risk.
- A calcium supplement on board — because no common feeder insect supplies enough calcium on its own.
Hold both feeders up against that list and the differences become obvious.
Discoid roaches: the better staple
Discoid roaches (Blaberus discoidalis) are a medium-large tropical roach native to Central and South America. They've become a favorite feeder for good reasons:
- Protein: roughly 20% as-fed — plenty for a skink.
- Fat: moderate, around 6–8%. This is the decisive number. A skink can eat discoids regularly without the weight problems that come with fattier feeders.
- Soft-bodied and low-chitin. Compared with a mealworm's hard shell, a discoid is much easier to digest and far gentler on a skink's gut, which lowers impaction risk — important for an animal you'll feed insects to for years.
- Easy to keep and breed. Discoids don't climb smooth walls and don't fly, so they're simple to contain, and a colony will reproduce and supply you long-term.
- Low odor, quiet. A big upgrade over crickets.
One myth to correct, because care sheets repeat it constantly: discoid roaches are not naturally calcium-rich or "close to the ideal 2:1 calcium-to-phosphorus ratio." Like virtually every feeder insect, they're phosphorus-heavy and low in calcium. Gut-loading helps their overall nutrition, but it does not fix the calcium gap — you still dust with a calcium supplement. Anyone telling you discoids let you skip calcium is wrong, and following that advice is a fast track to metabolic bone disease.
Mealworms: fine as a treat, weak as a staple
Mealworms (Tenebrio molitor) are the larvae of the darkling beetle — cheap, everywhere, easy to store (they even tolerate refrigeration), and eagerly eaten. Their weaknesses are specific:
- Protein: similar to discoids, around 20%.
- Fat: high, roughly 13–18%. That's the problem. For a slow-metabolism lizard that gains weight easily, a fatty feeder as the staple drives obesity over time.
- Hard, chitin-heavy exoskeleton. Mealworms are tougher to digest, and in quantity — especially for young or small skinks — that raises impaction risk. The hard shell is the single most-cited reason vets advise moderation.
- Poor calcium-to-phosphorus ratio. Strongly phosphorus-heavy; without diligent calcium dusting, a mealworm-heavy diet pushes a skink toward calcium deficiency.
None of this makes mealworms bad. As an occasional, gut-loaded, calcium-dusted treat, they're perfectly fine and add welcome variety. The mistake is making them the main protein because they're convenient.
Head to head
| Factor | Discoid roach | Mealworm |
|---|---|---|
| Protein (as-fed) | ~20% | ~20% |
| Fat | Moderate (~6–8%) | High (~13–18%) |
| Body / digestibility | Soft, low chitin, easy | Hard shell, harder to digest |
| Impaction risk | Lower | Higher (esp. juveniles) |
| Calcium | Low — must dust | Low — must dust |
| Containment | Doesn't climb/fly | Contained easily, can refrigerate |
| Long-term supply | Breeds readily at home | Breeds, but slower/less reliable |
| Best role | Staple protein | Occasional treat |
The pattern is clear: comparable protein, but discoids win decisively on fat and digestibility, the two factors that matter most for a skink's long-term health. That's why discoids belong in the bowl regularly and mealworms belong in the rotation occasionally.
The verdict and how to feed
For a blue tongue skink, make discoid roaches your staple insect protein and use mealworms as an occasional treat. Practically:
- Gut-load both for 24–48 hours before feeding — fresh produce and a quality dry diet — so the feeders carry real nutrition.
- Dust with calcium on your skink's schedule (and a calcium-plus-D3 or multivitamin periodically). This is non-negotiable for both feeders.
- Size the feeder to no larger than the space between the skink's eyes.
- Keep the diet varied — discoids as the protein anchor, mealworms and other feeders for variety, plus the all-important greens and a little fruit.
A roach colony is genuinely low-maintenance and pays for itself over a skink's long life. When you want healthy, well-started discoids sized for skinks, All Angles Creatures stocks discoid roaches for both colony-starting and direct feeding.
If you want the deeper picture on calcium, phosphorus, and metabolic bone disease in reptiles, the Merck Veterinary Manual's reptile nutrition section is a reliable, non-commercial reference.
Building your skink's feeder rotation? See my comparison of black soldier fly larvae vs. discoid roaches for blue tongue skinks, my full discoid roach breeder's playbook, or the complete feeder insect care library.