Picking the right Dubia roach size can feel like guesswork the first time. Order too small, and your hungry juvenile dragon has to chase dozens of tiny nymphs. Order too big, and you're feeding something your pet can't swallow safely. The good news is that sizing gets easy once you know a few simple rules.
This guide covers each Dubia size we carry at Dragon's Diet, which reptiles (and tarantulas) each size suits at different life stages, the "gap between the eyes" rule keepers rely on, and how to gut-load and dust your roaches so every bite counts.
Dubia Roach Size Chart (Dragon's Diet Sizes)
| Dragon's Diet size | Approx. length | Bearded dragon | Leopard gecko | Chameleon | Tarantula |
|---|---|---|---|---|---|
| Small 3/8" | 3/8" | Babies (roughly 0–3 months) | Hatchlings & juveniles | Babies & juveniles | Juveniles. Very small slings may need smaller prey |
| Medium | 3/8"–1/2" | Juveniles (roughly 3–8 months) | Sub-adults & most adults | Sub-adults & adults (smaller species) | Sub-adults & adults (medium species) |
| Large 3/4" | 3/4"–1" | Sub-adults & adults (roughly 8+ months) | Large adults only, with caution | Large adult veileds/panthers | Large adult species |
| Adult Male | 1.25"+ | Large, full-grown adults only | Not recommended | Generally not recommended | Very large adults only |
Ages are approximate. Your pet's actual size matters more than its age, so always check with the eye-gap rule below.
Ready to stock up? Browse every size in our Dubia roaches for sale, or go bulk with Bulk Small Dubia Roaches and Bulk Medium Dubia Roaches.
The Golden Rule: The Gap Between the Eyes
The most widely used sizing rule in the reptile hobby is simple: never feed an insect wider than the space between your reptile's eyes.
Here's how to use it:
- Look at your pet head-on (or snap a photo from above next to a ruler).
- Estimate the distance between the eyes. That's the most you want a feeder's width to be, not its length.
- Compare it to the roach. Dubias are broad, flat insects, so a Dubia is wider than a cricket of the same length. When in doubt, go one size down.
If you're between two sizes, pick the smaller one. You can always offer a few more small roaches. You can't make a too-large roach smaller.
Why the Right Size Matters
Size is about more than convenience. Prey that's too large can:
- Be hard to swallow. Oversized feeders can lead to gagging or regurgitation.
- Contribute to impaction risk. Large, hard-bodied insects are harder to digest, especially for young reptiles or a pet that's too cool to digest well. Proper basking temperatures help digestion too. Read more in our guide to bearded dragon impaction.
- Stress your pet. A baby reptile that struggles with big prey may lose interest in feeding.
Prey that's too small is less risky but less efficient. Adults may have to eat a huge number of tiny nymphs, and some lose interest. The right size means fewer, more satisfying meals.
If your pet is gagging, regurgitating, straining, or not passing stool, talk to a reptile veterinarian. Don't just change feeder sizes.
Bearded Dragons: Dubia Size and Feeding Amounts by Age
Bearded dragons are the reason many keepers switch to Dubias. They're meaty, slow-moving, quiet, and easy to keep. (Curious how they compare? See Dubia roaches vs crickets.)
The ranges below are general guidance that keepers commonly use. Every dragon is different, so watch body condition and appetite and adjust with your vet's input.
| Stage (approx.) | Dragon's Diet size | How often | General amount |
|---|---|---|---|
| Baby (0–3 months) | Small 3/8" | 2–3 feedings a day | Offer as many as they eagerly eat in roughly 10–15 minutes |
| Juvenile (3–8 months) | Small → Medium (3/8"–1/2") | 1–2 feedings a day | As many as eaten in a 10–15 minute session, with daily greens |
| Sub-adult (8–18 months) | Medium → Large 3/4" | About once a day, shifting toward more greens | Fewer insects, more salad |
| Adult (18+ months) | Large 3/4" (Adult Male occasionally for big dragons) | A few insect meals a week | A modest portion. Greens make up most of the diet |
Remove uneaten roaches after the session so they don't wander the enclosure. For the full picture, see our bearded dragon feeding chart by age, the complete bearded dragon diet plan, and how big bearded dragons get.
Tip: Dragons grow fast in their first year. Re-check the eye gap every few weeks, because last month's perfect size may be too small now.
Leopard Geckos
Leopard geckos do great on Dubias, but they have smaller mouths than a dragon the same age, so size down.
- Hatchlings and juveniles: Small 3/8"
- Most adults: Medium (3/8"–1/2")
- Large adults: an occasional Large 3/4", only if it passes the eye-gap test
Leos hunt by movement, and Dubias tend to burrow, so a smooth-sided feeding dish or feeder tweezers help keep roaches in view. Learn more in Can leopard geckos eat Dubia roaches? and What do leopard geckos eat?
Chameleons
Chameleons hunt with their tongue, often from a branch, so prey needs to be easy to see and easy to grab.
- Babies and juveniles: Small 3/8"
- Sub-adults and adults: Medium (3/8"–1/2"). Big adult veileds and panthers may take Large 3/4"
Dubias don't climb smooth surfaces, so many keepers offer them in a cup or dish attached to a branch. Chameleons drink from droplets, not bowls, so a well-hydrated roach is a small bonus. More species care tips are on our Chameleon Care blog.
Tarantulas
Tarantulas are a great match for Dubias, which don't bite and won't harm a molting spider the way some feeders can.
- Slings: the smallest Dubias available. Our Small 3/8" suits larger slings and juveniles
- Juveniles: Small 3/8"
- Adults: Medium (3/8"–1/2") for most species. Large 3/4" for big species
A common hobby guideline is prey roughly the size of the tarantula's body (abdomen), or a little smaller. Don't feed a tarantula that's in premolt or freshly molted. Take uneaten prey out within a day. See What do pet tarantulas eat?
Gut-Loading and Dusting: Make Every Roach Count
The right size gets the roach down safely. Gut-loading and dusting make it nutritious.
Gut-loading means feeding your roaches a quality diet for 24–48 hours before they're offered, so those nutrients pass on to your pet. Dubias are great at this because they're steady eaters.
- Feed a dedicated diet like Dubia Roach Chow, plus fresh veggies such as carrot or leafy greens.
- Hydrate them safely with Bug Chug Water Crystals instead of an open water dish they can drown in.
- Keep them in a ventilated tub such as a Critter Keeper. For long-term keeping, see Dubia roach care.
Dusting means coating feeders in a calcium supplement right before feeding. Put a few roaches in a bag or cup with a pinch of powder, give them a gentle shake, and serve. Try our Reptile Greens & Calcium Powder or browse vitamins & supplements. How often to dust depends on age, species, and UVB setup. Our guides on calcium and vitamin D3 and how to give your bearded dragon calcium walk through it. Your vet can tailor a schedule.
(Tarantulas don't need dusting. Just gut-load well.)
Dubia Roach Size Chart FAQ
What size Dubia roach should I feed a baby bearded dragon? Small 3/8". Check that the roach isn't wider than the gap between your dragon's eyes.
What size Dubias for an adult bearded dragon? Most adults do well on Large 3/4". Big, full-grown dragons can take an occasional Adult Male.
Can I feed Dubias that are too small? Yes. Small prey is safe, just less efficient. Offer a few more per meal, or size up when your pet passes the eye-gap test.
How do I measure a Dubia roach? Measure body length from head to tail tip. Remember Dubias are wide, so judge width against your pet's eye gap too.
How many Dubias should I order? It depends on how many animals you have and how old they are. Babies eat the most insects. Many keepers start with 50–100 and adjust. Bulk sizes save money for multi-pet homes. See Live Insect Feeding 101 for handling tips.
Will Dubias grow into the next size? Yes. Kept warm and fed, nymphs grow over time, so a mixed colony gives you several sizes. Here's how to start breeding Dubia roaches.
Are Dubias good for every reptile? They're an excellent staple for many insect-eaters. Read Are Dubia roaches good feeders for reptiles? for the details.
Find Your Size
Measure the eye gap, check the chart, and when in doubt, size down. When you're ready, our Dubia roaches ship in Small, Medium, Large, and Adult Male. You can also browse our full lineup of live feeder insects. Happy feeding!
