Silkworms vs Waxworms: The Healthy Treat vs the Junk Food
Both silkworms and waxworms are feeders reptiles go nuts for. That's where the similarity ends. Silkworms at roughly 1% fat are the leanest feeder I keep; waxworms at around 25% fat are the fattiest. One is a premium supplement I offer my geckos two or three times a week without a second thought. The other is junk food that creates genuine behavior problems when it's overused. If you only take one comparison away from this site, make it this one.
The numbers
| Category | Silkworms | Waxworms |
|---|---|---|
| Fat | ~1% | ~25% |
| Protein | ~9% | ~14% |
| Addictive? | No | Yes — highly |
| Obesity risk | Minimal | Very high |
| Serrapeptase enzyme | Yes | No |
A 25-to-1 fat gap is not a rounding error. It's the difference between a feeder you can build into a weekly routine and one that, fed regularly, tips an animal toward an obese tail, fatty liver, and a stubborn refusal to eat anything else.
The waxworm addiction problem
This is the part new keepers don't see coming until it's a real headache. Waxworms are so fatty and palatable that many leopard geckos and bearded dragons become genuinely addicted — they'll refuse roaches, silkworms, everything, and simply hold out for more waxworms. Breaking that standoff can mean a week or two of food refusal, some weight loss, and a lot of stress for both the animal and the keeper. I've coached people through it, and it's avoidable misery.
Silkworms trigger an equally strong feeding response without the hook. A gecko will hammer silkworms eagerly and then happily take roaches or BSFL at the next meal. No holdout, no refusal cycle, no behavior to undo.
When to use each
Silkworms: a regular supplement, two to three times a week. Safe, lean, hydrating (they're ~83% moisture), and they carry serrapeptase, an enzyme thought to support digestion. This is the treat you can offer without guilt.
Waxworms: a rare emergency tool — once every two weeks at the absolute most, and really only for coaxing a critically sick animal back onto food. Plenty of experienced keepers, myself included, skip them entirely.
If you're currently using waxworms as a routine treat, swapping to low-fat silkworms gives your gecko the same enthusiastic response with about 25 times less fat and zero addiction risk. It's one of the easiest upgrades you can make to a reptile's diet.
This is the core principle behind how to prevent reptile obesity, and there's a parallel story in silkworms vs superworms.
Sources: Finke, M.D. (2002). "Complete nutrient composition of commercially raised invertebrates." Zoo Biology 21:269-285. doi:10.1002/zoo.10031 · MSD Veterinary Manual — Nutrition in Reptiles