Discoid Roaches vs. Nightcrawlers for Skinks: How I Use Both

I keep skinks, and the question I get more than almost any other is some version of "roaches or worms?" People want a winner. The honest answer is that discoid roaches and nightcrawlers aren't competing for the same job, so picking one over the other is the wrong frame entirely. One is your protein staple. The other is a hydrating, soft-bodied supplement. The skinks I keep in the best condition get both, on a rotation, and this guide is exactly how I run that rotation — the diet ratios, the sizing, the gut-loading, and the calcium routine that ties it all together.

I'm also going to fix a few things you'll read elsewhere (including, embarrassingly, in older versions of my own writing). There's a lot of repeated misinformation about these two feeders, and getting it wrong can genuinely hurt your animal. So this is the accurate version.

First, what your skink actually needs

"Skink" covers a huge range of lizards, so start with your species. The split that matters most for feeding is omnivore vs. insectivore.

Blue-tongue skinks — the most commonly kept skink in the hobby — are omnivores. A healthy adult blue-tongue diet is roughly half plant matter (leafy greens, squash, bell pepper, and other safe vegetables, with a little fruit) and half animal protein. The feeders in this article fill that protein half. They do not replace the greens, and an all-bug diet is one of the most common ways well-meaning keepers slowly make a blue-tongue sick.

Other common skinks lean more insect-heavy — fire skinks, many smaller terrestrial species — and will take a higher proportion of live prey. But every skink I keep, omnivore or not, runs on the same two principles: vary the protein, and dust it with calcium. Discoids and nightcrawlers are the two feeders I lean on hardest to do that, and they cover different bases.

Discoid roaches: the protein staple

Discoid roaches (Blaberus discoidalis) are the feeder I build a skink's protein around. Here's why they earn the "staple" label.

What's actually in them

Treat all feeder numbers as approximate — they swing with diet, life stage, and source — but as-fed, a discoid runs roughly 20% protein, 6–7% fat, and 60–65% moisture. That's a lean, protein-forward profile with moderate fat, which is exactly what you want in a feeder you're going to use regularly. They won't fatten a skink the way superworms will, and they carry real protein without being mostly water.

They're also low-chitin and soft-bodied. This is worth being precise about, because you'll see it described both ways: discoids have a soft, low-chitin exoskeleton compared to crickets or mealworms — not a hard one. That softness is a genuine health feature for skinks, because it makes the roach easier to digest and lowers the risk of impaction, especially in juveniles, older animals, or any skink with a sensitive gut.

The containment advantage everyone gets backwards

Here's the fact I most want to correct: adult discoid roaches do not climb smooth vertical surfaces. Glass, smooth plastic — they can't grip it. You'll find sources (mine included, once) claiming discoids are "excellent climbers" that escape easily. That's flatly wrong, and it's actually backwards: their inability to scale smooth walls is one of the best reasons to use them. Drop them in a smooth-sided feeding bowl and they stay put for your skink to hunt; keep your colony in a plain bin and adults won't walk out.

They don't fly, either. The only real containment caveat is that newborn nymphs are pinhead-sized and can slip through coarse ventilation holes on a holding bin — which fine metal mesh over the vents solves completely. That's a holding-bin detail, not a reason to avoid the feeder.

Calcium: the honest version

Discoids are nutritious, but like nearly every feeder insect they are phosphorus-heavy — the calcium-to-phosphorus ratio is poor no matter how well you gut-load. I want to be clear about this because you'll see claims that discoids hit a tidy 2:1 calcium-to-phosphorus ratio. That isn't reliable; feeder insects in general lean toward phosphorus. So gut-loading improves what's inside the roach, but it does not fix the calcium gap. You close that gap by dusting with a calcium supplement, every time, which I'll cover below.

If you want the deep dive on running a healthy discoid colony at home — heat, humidity, breeding, harvesting — I wrote a full playbook on how to keep discoid roaches alive.

Nightcrawlers: the hydrating supplement

Nightcrawlers (Lumbricus terrestris) are the other half of how I feed skinks — but their role is different, and getting that role right depends on reading their nutrition honestly.

Mostly water, and that's the point

Nightcrawlers are very high moisture — roughly 80–85% water as fed. That single fact defines everything about how to use them. You'll sometimes see nightcrawlers described as "60–70% protein," which is misleading: that's a dry-matter figure, measured after all the water is removed. On an as-fed basis — the worm as your skink actually eats it — a nightcrawler is mostly water, with moderate protein and low fat on a dry basis once you account for that.

So a nightcrawler is not a protein powerhouse in the bowl. It's a hydration delivery system that happens to carry some protein. That makes it genuinely useful — especially for a skink that's a little dehydrated, going through a shed, or living somewhere dry — but it's why I treat worms as a supplement, not a staple. You can't build a skink's protein intake on something that's four-fifths water.

Soft, digestible, and easy on delicate jaws

The flip side of all that moisture is that nightcrawlers are extremely soft and easy to digest. No exoskeleton at all means no chitin and a very low impaction risk. That makes them one of the best feeders for juvenile skinks, elderly skinks, or any animal with reduced jaw strength or a sensitive stomach. When I've got a skink that's struggling with firmer prey, a piece of nightcrawler is often the thing it can handle easily.

Calcium and sourcing caveats

Nightcrawlers are also imbalanced — their mineral profile leans toward phosphorus, so they too need calcium dusting before feeding. Don't let "worms have calcium" fool you into skipping it; the ratio isn't ideal.

Two more practical notes. First, source clean worms — bait shop, garden center, or a feeder supplier, never collected from soil that might be treated, because pesticides and parasites in wild worms are a real risk to your skink. Second, nightcrawlers are needier to keep alive than roaches: they want a cool (around 40–50°F, a fridge works), damp, well-ventilated container, and bedding kept moist but never soggy. They're a feeder you buy in modest amounts and use, not a self-sustaining colony.

The honest head-to-head

Here's how the two stack up on the things that actually drive a feeding decision. Treat the figures as approximate, as-fed:

The takeaways that matter:

• ◆Discoids carry the protein. Real, lean protein that isn't mostly water, in a soft body that's easy on a skink's gut. That's a staple.
• ◆Nightcrawlers carry water and gentleness. Great for hydration and for skinks that need the softest possible prey, but too water-heavy to anchor a diet.
• ◆Both need calcium dusting. Neither has a ratio that lets you skip it.
• ◆Variety beats any single feeder. Rotating the two — plus greens for omnivores — gives you a better diet than leaning on either one.

How I run the rotation

This is the part people actually want: what to do week to week.

Diet ratios

For an omnivorous blue-tongue skink, I aim for roughly half greens/vegetables, half protein. Within that protein half, discoids are the regular workhorse and nightcrawlers come in as a rotating supplement — think the majority of protein feedings as discoids (and other insects), with nightcrawlers worked in maybe once a week or so, and more often if the animal needs the extra moisture.

For a more insectivorous skink, the protein share is larger, but the same logic holds: discoids as the everyday base, nightcrawlers as the soft, hydrating change-up rather than the main event.

Adjust to the animal in front of you. A skink that's getting chunky gets leaner feedings and smaller portions; a skink mid-shed or looking a touch dehydrated gets a nightcrawler day.

Sizing to the skink

The universal rule: no feeder wider than the space between the skink's eyes. For discoids that means choosing the right nymph size — small nymphs for small or juvenile skinks, medium-to-large nymphs (and adults) for a full-grown blue-tongue. Because discoids come in a full range of sizes, you can dial this in precisely, which is another reason they make such a good staple. For nightcrawlers, cut them to size — a big worm can be snipped into appropriate sections for a smaller skink rather than offered whole.

Gut-loading the discoids

What the roach eats becomes what your skink eats. For 24–48 hours before you feed off, give your discoids good produce (carrot, squash, leafy greens) plus a quality protein base. Gut-loading meaningfully improves the nutrition inside the feeder — just remember it does not fix the calcium ratio. Nightcrawlers you simply keep clean and well-bedded; you're not gut-loading them so much as keeping them healthy until use.

The calcium routine

Every feeding, dust your feeders with a reptile calcium supplement. I rotate plain calcium for most feedings and a calcium-with-D3 or a multivitamin on a schedule appropriate to the species and its lighting setup. This applies to both discoids and nightcrawlers, every time. Toss the feeders in a little supplement before they go in the bowl. This single habit, more than any feeder choice, is what prevents metabolic bone disease.

A simple weekly shape

For a healthy adult blue-tongue, a week might look like: greens-forward meals most days, discoids (dusted) on the protein days, a nightcrawler day worked in for hydration and variety, and the occasional other protein — egg, lean meat, or a different insect — to keep the diet broad. Juveniles eat more often and more protein-heavy; seniors eat less and appreciate the softer feeders. Watch body condition and adjust.

The bottom line

Stop thinking of it as discoids or nightcrawlers. Discoid roaches are your protein staple — lean, soft, easy to digest, easy to size, and (despite what you'll read) impossible for adults to climb out of a smooth bowl. Nightcrawlers are your hydrating supplement — mostly water, gentle on delicate jaws, perfect for variety and for skinks that need the moisture. Run both in a rotation, dust everything in calcium because neither has an ideal ratio, keep omnivores on their greens, and size every feeder to the animal. Do that and you're feeding a skink properly — not betting its health on one bug.

When you need a reliable, well-started supply for the staple side of that rotation, All Angles Creatures stocks healthy discoid roaches sized for everything from small skinks to full-grown blue-tongues.

Want more on building a skink's protein rotation? See my breakdown of wax moth larvae vs. discoid roaches for blue-tongue skinks.