(Source: B. Trevarrow from Zebrafish Book 5th Edition)
Microworms are a live food that some labs are using instead of brine shrimp. Here is a method for raising microworms adapted from techniques used in fly labs.
Materials
- Clean plastic boxes with snap on lids (Tupperware‑like)
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Establishing the worm cultures
1. Make up the oatmeal in the approximate proportions of 150 ml of oatmeal to 400 ml of distilled water. The proportions should be adjusted to give a thick but not overly firm consistency.
2. Soak the oatmeal for about 5‑10 minutes, then boil in a double boiler for about 5‑10 minutes (until the oatmeal is evenly thick from the top to the bottom).
3. Remove the oatmeal from the heat and add 2.8 ml of 10% methyl‑p‑hydroxybenzoate in 95% EtOH for every 400 ml of oatmeal mixture, to yield a final concentration of 0.07%. Stir and pour into the clean plastic boxes. After the mixture cools, add an aliquot of microworms.
4. Check the new cultures in about a week for worms. They should be climbing out of the culture onto the sides of the container or squirming visibly in the culture medium. Some cultures may take longer to produce a good crop of worms. If they do not produce worms by the second week, rinse and bleach the containers before reusing. Old cultures that no longer produce worms should be discarded and the containers washed and bleached before reuse.
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6. Add more water to the first tube and wash remaining worms onto the sieve.
7. Fill the second tube with additional water until the level just reaches the bottom of the sieve. Live worms will wiggle through the sieve into the water, dead worms and pieces of food are retained and should be discarded.
8. Let the live worms settle to the bottom (5‑15 min).
9. Remove the worms from the bottom of the tube with a Pasteur pipette and transfer to a small tube for distribution to the fish tanks.
10. Live worms can be maintained for extended periods in the large or small tubes without any problems.