Dubia Roach Sizes Explained XS to XL | Size Guide
Understanding dubia roach sizes is important for feeding reptiles safely and effectively. Unlike some feeder insects (mostly mealworms and superworms which are easier to grade accurately), dubia roaches are not sorted into exact individual sizes, but instead grouped into size ranges. Kind of like frozen feeders are grouped into weight ranges.
Choosing the right size feeder is important to ensure your reptile doesn't get a food item that's too big, but also not one so small it has to eat hundreds of them. This guide explains how dubia roach sizes work, how they are graded, and why size variation is completely normal. For a broader overview of feeder insects, see our complete guide to feeder insects in Australia.
Quick takeaway: Dubia roaches are sold in size ranges, not exact sizes. Width-based grading is more accurate than length, and natural variation is expected due to growth and feeding.
Why Dubia Roaches Are Sold in Size Ranges
Dubia roaches cannot be sorted into perfectly identical sizes. Even within the same age group, individual roaches vary drastically in size due to natural growth differences.
Factors that affect size variation include:
- Feeding: Recently well-fed roaches appear larger and fuller
- Hydration: roaches expand and contract based on moisture levels
- Growth stage: roaches develop in instars, not fixed sizes
- Genetics: some individuals naturally grow larger or smaller
Because of this, suppliers use size ranges instead of exact lengths or ages. This ensures consistency while still accounting for natural variation.
Why Width Is More Accurate Than Length
Dubia roaches are graded based on width rather than length. This is because length can vary depending on how stretched or compressed the roach is at the time of measurement. This can be caused by themselves, but also by recently consuming food or water.
Width provides a more consistent and practical measurement because:
- It reflects the actual bulk of the roach
- It is more relevant for feeding safety
- It is less affected by movement or posture
Since dubia roaches can expand after feeding and contract when empty, width-based grading is the most reliable method used in commercial sorting.
How Dubia Roaches Are Graded (Screen Method)
Dubia roaches are commonly graded using different sized holes, most commonly, perforated metal, acrylic or plastic sorters, commonly referred to as 'screens' are used. Each Dubia size is defined by which screen the roaches fall through and which screen they are retained on.
The grading system we use for our sizes here at Reptifauna is a fairly standard sizing system used world wide:
- XS: below 4mm screen, on top of 3mm screen
- Small: below 6mm screen, on top of 4mm screen
- Medium: below 10mm screen, on top of 6mm screen
- Large: below 12mm screen, on top of 10mm screen
- XL: below 14mm screen, on top of 12mm screen
This method ensures each size group stays within a consistent range while allowing for natural variation within that range.
Adult Dubia Roach Sizes
Adult dubia roaches are not uniform in size, especially when comparing males and females.
- Adult males: usually sit on the 12mm screen, but smaller individuals can occasionally pass through
- Adult females: typically sit on both 12mm and 14mm screens due to their larger and more variable body size
Female dubia roaches are bulkier because they carry developing young internally, which contributes to their wider size range. They can change drastically in thickness between being close to giving birth, and recently having babies.
How Growth and Feeding Affect Size
Dubia roaches do not stay at a fixed size. Their appearance can change depending on feeding and hydration.
- Well-fed/hydrated roaches: appear larger and more rounded
- Recently fed: expand slightly in width
- Dehydrated roaches: appear 'compressed' and thinner
- Growing nymphs: increase in size gradually through molts
This is another reason why exact sizing is not practical. Even within the same batch, roaches may look slightly different depending on when they last ate or drank.
To improve feeder quality, see: How to Gut Load Feeder Insects
Common Mistakes to Avoid
- Expecting perfectly identical roach sizes
- Measuring by length instead of width
- Choosing feeder size without considering reptile size
- Assuming all adults are the same size
Choosing the Right Size Dubia Roaches
Choosing the correct size is important for safe feeding. As a general rule, the feeder should not be wider than the space between your reptile’s eyes.
Here at Reptifauna, we offer several different sizes and have images of the variation next to a tape measure for easy reference.
Related Guides
Final Thoughts
Dubia roach sizing is based on ranges, not exact measurements. Understanding how they are graded and why variation exists will help you choose the right feeders and set realistic expectations.
By focusing on width, you can confidently select the right size dubia roaches for your reptiles. Keep in mind, if some of the dubia are too small to feed right away, you can always hold onto them for a week or two until they grow to the correct size.
