How to Keep Mealworms Alive for Weeks (Complete Care Guide)

You've just received a tub of live mealworms — now what? Stored correctly, mealworms can stay alive and healthy for 4–6 weeks or longer. Stored wrong, you'll find a tub of pupae, beetles or worse within days. Here's exactly how to keep them thriving.

The short version

Keep them cool (8–15°C), dry, fed on wheat bran, and give them moisture through fresh veg — never open water. That's 90% of it. The details below cover the rest.

Step 1: Get them out of the shipping tub

The tub your mealworms arrive in is designed for transit, not long-term storage. Within a day of arrival, transfer them to a larger, smooth-sided plastic container — something like a 2–5L tub with ventilation holes in the lid. More space means less heat build-up and slower die-off.

Step 2: Bedding that doubles as food

Add 2–3cm of wheat bran to the container. Bran is both bedding and food, which is why it's the standard substrate for mealworm keeping. The worms burrow into it and graze continuously. Top it up as it gets eaten down — if you see more frass (fine sandy droppings) than bran, it's time to refresh.

Step 3: The temperature decision

This is where most people go wrong. Mealworms are the larval stage of the darkling beetle, and at room temperature they're on a countdown to pupation. You have two options:

Cool storage (recommended for feeders): 8–15°C dramatically slows their metabolism and pauses pupation. The fridge door shelf or a cool garage in winter is ideal. At this temperature they need very little food and can last 6+ weeks. Take them out for a few hours once a week to let them feed at room temperature, then return them.

Room temperature (for gut-loading or growing): 20–25°C keeps them active and feeding, which is what you want in the 24–48 hours before feeding them off — an actively feeding worm passes more nutrition to your pet. The trade-off: they'll start pupating within 1–3 weeks.

Never freeze live mealworms, and don't store them below 5°C for extended periods.

Step 4: Moisture without drowning

Mealworms get water from food, not from drinking. A slice of carrot, potato or apple every few days does the job — remove it before it moulds. Open water dishes kill mealworms. If you want a set-and-forget option, water crystals provide drown-proof hydration.

Step 5: Gut-loading before feeding off

Whatever your mealworm ate in the last 24–48 hours is what your gecko, dragon or bird gets. Before feeding off, bring a batch to room temperature and let them feed heavily on fresh bran and veg. Then dust with a calcium supplement at feeding time — mealworms are naturally low in calcium relative to phosphorus, and dusting corrects the balance for reptiles.

Troubleshooting quick answers

My mealworms are turning into white curled things. Those are pupae — the worms were kept too warm for too long. Pupae are still edible for most pets, but move remaining worms somewhere cooler.

There are black beetles in my tub. Pupae you missed have hatched into darkling beetles. Feed them off to larger pets or start a breeding colony — beetles lay eggs that become your next generation of free mealworms.

The bran smells damp or musty. Too much moisture. Remove wet veg, replace the bran, and increase ventilation.

Worms are dying at the bottom of the tub. Usually overcrowding and heat. Split them into two containers.

Shop the setup

Everything mentioned here is available from us: live mealworms from R35, wheat bran/worm chow, water crystals and calcium supplements — delivered anywhere in South Africa.