Discoid Roaches vs. Hornworms for Crested Geckos
Hornworms are the feeder that makes new keepers gasp — they're huge, neon green, and your gecko lunges at them like it hasn't eaten in a week. That dramatic reaction fools a lot of people into thinking hornworms are a superfood. They aren't. They're a hydration treat dressed up as a meal. Discoid roaches and hornworms both belong in a thoughtful feeding plan, but they do completely different jobs, and confusing the two is a common, avoidable mistake. Let me explain how I use each.
Frame it right: insects supplement the staple diet
Start with the foundation. A crested gecko (Correlophus ciliatus) is an omnivore whose captive diet is built on a complete commercial crested gecko diet (CGD) — the fruit-and-protein powders like Pangea and Repashy. Live insects are a supplement, offered once or twice a week for protein and enrichment. So this comparison is about which supplemental feeder does what, on top of that staple CGD. (For the full care picture, see the exotic animal care hub.)
Discoid roaches: the protein staple
Discoid roaches (Blaberus discoidalis) are the workhorse supplemental feeder:
- Real, lean protein, roughly 20–23% protein with 4–7% fat — a clean protein boost that supports growth and muscle without piling on fat.
- Soft, low-chitin body that digests easily and carries a low impaction risk, which matters for small cresties.
- Hydrating, around 65–75% moisture.
- Practical to keep: long-lived in a simple bin, cheap to feed, non-climbing on smooth walls, non-flying, and barely any odor.
- Size range from tiny nymphs for hatchlings to larger nymphs for adults.
The honest caveat, true of nearly every feeder: discoids are phosphorus-heavy, so you must dust them with calcium — ignore the recycled claim about a "balanced ratio." For a self-sustaining supply, see my discoid breeding playbook; to buy them sized and ready, All Angles Creatures stocks discoid roaches suited to cresties.
Hornworms: the hydration treat
Hornworms (Manduca sexta) are the larvae of the hawk moth — big, soft, bright green caterpillars. Their strengths are genuine but narrow:
- Very high moisture, around 85–90% water, which makes them excellent for hydration and a good tool for a gecko that's looking a bit dry or has been off its food.
- Extremely soft, with no tough exoskeleton, so they're easy to digest even for young or delicate geckos.
- A favorable mineral balance compared with many feeders — decent for calcium, though still worth a light dusting.
- Irresistible. Their color and slow, undulating movement trigger an immediate feeding strike, which makes them a great way to tempt a picky eater.
Now the limits that disqualify them as a staple:
- Barely any protein — only about 9% — and very low fat (~3%). They're mostly water, so they can't build or sustain a gecko on their own.
- Overfeeding causes loose stools because of that high water content.
- They grow explosively and are hard to keep: they need a specific commercial diet (their natural tomato/tobacco foliage is toxic to reptiles), have a short usable window before they get too large or pupate, and ship delicately.
- Size creep. A hornworm can quickly outgrow a safe size for a small crestie, becoming a choking risk.
When you want them for hydration or to coax a reluctant eater, All Angles Creatures carries hornworms — just use them for what they're good at.
Head-to-head
| Factor | Discoid roach | Hornworm |
|---|---|---|
| Protein | High (~20–23%) | Low (~9%) |
| Fat | Low (~4–7%) | Very low (~3%) |
| Moisture | ~65–75% | Very high (~85–90%) |
| Calcium / Ca:P | Phosphorus-heavy — must dust | More favorable — dust lightly |
| Digestibility | Soft, low chitin | Very soft |
| Keeping | Easy, long-lived | Fussy, fast-growing, short window |
| Best role | Protein staple | Hydration / picky-eater treat |
How I use both
These two complement each other perfectly when you respect their roles:
- Discoid roaches as the regular insect supplement, sized no larger than the space between the gecko's eyes, gut-loaded 24–48 hours ahead and dusted with calcium every feeding.
- Hornworms as an occasional treat — for hydration, to tempt a gecko that's gone off its food, or just for variety and enrichment — never as the main feeder.
- Watch the stool after hornworms; if it goes loose, scale them back.
- Follow reptile supplementation guidance for calcium and D3, and feed in the evening when cresties are active.
The verdict
This isn't really a contest — it's a division of labor. Discoid roaches are the protein staple; hornworms are the hydration treat. Build your crested gecko's insect rotation on calcium-dusted discoids, reach for hornworms occasionally to hydrate or tempt a finicky eater, and keep a complete CGD as the foundation under both. Mistaking the hornworm's dramatic appeal for nutrition is the trap; use each feeder for its real job and your gecko thrives.
Comparing other crested gecko feeders? See discoid roaches vs. silkworms and the crested gecko feeder debate, or browse the full exotic animal care library.