Black Soldier Fly Larvae Care Guide: Storage, Feeding & FAQ
Matt GorenShare
How to Store and Feed Black Soldier Fly Larvae
Black soldier fly larvae (BSFL, Hermetia illucens) are one of the easiest feeder insects to store at home. Unlike silkworms that need mulberry chow or hornworms that grow explosively, BSFL simply go in the refrigerator and wait until you need them. No feeding required during storage, no special containers, no daily maintenance.
This guide covers everything you need to know about keeping BSFL alive, healthy, and nutritious at home.
Storage: The Refrigerator Method
BSFL storage is remarkably simple. Place them in the refrigerator at 50-55°F and they enter a dormant state — metabolism slows dramatically, they stop moving around, and they survive for 2-3 weeks with zero maintenance.
Step by Step
- Receive your BSFL order and open the container
- If they arrived in a cup with bedding, you can store them in the same container
- Place in the refrigerator — the door shelf or a dedicated spot on a shelf works fine
- That is it. No feeding, no watering, no cleaning needed during refrigerated storage.
- When ready to feed, remove the number you need and let them warm to room temperature for 10-15 minutes
- Offer to your reptile or sprinkle for your chickens
Temperature Guide
| Temperature | Shelf Life | Activity Level | Notes |
|---|---|---|---|
| 50-55°F (fridge) | 2-3 weeks | Dormant | Ideal storage — no maintenance needed |
| 55-65°F | 1-2 weeks | Slow | Cool room or basement |
| 70-80°F (room temp) | 5-7 days | Active | Will begin pupating faster |
| Below 40°F | — | Dead | Too cold — do NOT freeze BSFL |
Do BSFL Need to Be Fed?
No. Unlike discoid roaches or silkworms that need regular food, BSFL do not need to eat during storage. They have enough stored energy in their bodies to survive weeks in the fridge without any food or water. This is one of their biggest convenience advantages.
BSFL Life Cycle
Understanding the life cycle helps you time purchases and storage:
- Larval stage (what you buy): The plump, cream-to-dark-brown grub. This is the feeding stage with the highest calcium content.
- Pre-pupal stage: The larva darkens to brown/black and becomes harder. Still edible but less nutritious and less appealing to some reptiles.
- Pupal stage: The larva forms a hard brown shell. Not useful as a feeder.
- Adult fly: A wasp-like fly (harmless). Not typically fed to reptiles.
Refrigeration slows progression through these stages. At room temperature, larvae will pupate within 1-2 weeks. In the fridge, pupation is delayed for weeks.
How Many BSFL to Feed
| Animal | BSFL per Feeding | Frequency |
|---|---|---|
| Baby bearded dragon | 10-20 | Daily (part of mix) |
| Adult bearded dragon | 10-20 | 2-3x per week |
| Leopard gecko | 5-10 | 2-3x per week |
| Chameleon | 5-10 | 1-2x per week |
| Backyard chicken (per bird) | Handful (~50-100) | Daily treat |
Do You Need to Dust BSFL with Calcium?
No. This is the single biggest advantage of BSFL over every other feeder insect. At approximately 9,340 mg/kg calcium with a Ca:P ratio of 6.92:1, BSFL are naturally calcium-loaded. No other common feeder insect comes close. You can offer them straight from the container without any supplementation and your reptile receives a significant calcium boost.
That said, some keepers still lightly dust BSFL with a multivitamin (not calcium) once per week for broad-spectrum vitamin coverage. This is a matter of preference, not necessity.
Common Questions
Can I freeze BSFL?
No. Freezing kills BSFL. Some keepers freeze them intentionally and offer thawed larvae as dead feeders, but most reptiles prefer live prey. For live feeding, keep them refrigerated only — never frozen.
Why are my BSFL turning dark?
Darkening indicates they are entering the pre-pupal stage. They are still edible at this point but will soon pupate. Feed them to your reptile promptly. Refrigeration slows this process significantly.
My reptile ignores BSFL. What do I do?
BSFL are relatively sedentary compared to discoid roaches or crickets. Try offering them in a small dish where their concentrated wriggling is more visible. Some keepers wiggle a single BSFL with tongs to trigger a feeding strike. Mixing BSFL with more active feeders in the same dish also works.
Are phoenix worms, calciworms, and nutrigrubs the same thing?
Yes. Phoenix Worms, CalciWorms, ReptiWorms, and NutriGrubs are all brand names for the same insect: Hermetia illucens, the black soldier fly larva.
BSFL in Your Feeding Rotation
BSFL work best as a calcium-boosting supplement alongside other feeders:
- Daily staple: Discoid roaches (protein)
- 2-3x/week: Silkworms (low-fat premium)
- 1-2x/week: BSFL (calcium boost — no dusting needed)
- 1-2x/week: Hornworms (hydration)
This four-feeder rotation covers protein, low-fat nutrition, calcium, and hydration — the most complete feeding program for captive reptiles.
— Matt, Founder, All Angles Creatures
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