A Guide to Keeping and Breeding Walter-Worms

Discussion in 'Articles' started by Aquarist, Feb 5, 2021.

  1. Aquarist

    Aquarist Kevin

    Feb 5, 2021
    Likes Received:
    Pretoria, South Africa
    Nematode [noun]:
    1. A worm-like organism that belongs to the Phylum Nematoda.

    Walter-worms are non-parasitic nematodes that are consumed by several species of ornamental freshwater fish, including bettas (Siamese fighting-fish), cardinal-tetras, ember-tetras, exclamation-point rasboras, green tetras, guppies, kubotai-rasboras, lemon-tetras, neon tetras, scarlet badis, and zebra-danions. Additionally, Walter-worms are consumed by the aquacultured fry of many such species, including the fry of angelfish and the fry of killifish.


    One could accommodate a colony of Walter-worms in a clean plastic container whose lid has been perforated.

    One who would harvest Walter-worms daily is advised to use a container that has a capacity of at least 100 ml.

    Before placing the lid on a container, one is advised to cover the opening of the relevant container with a barrier that would prevent insects from entering the relevant container without preventing the diffusion of air. To fashion such a barrier, one could cut a suitably-sized circle, rectangle, or square out of a thin garment such as a stocking.

    Cultural Medium

    Walter-worms feed on bacteria, which require a suitable cultural medium, such as a mixture of brown or white bread and tap-water, which one could prepare in a blender by using 45 ml of water for every slice of bread that one uses.

    Ideally, the temperate of the water that one uses should be at or near room-temperature.

    Since the addition of yeast has been shown to prevent the growth of fungi on cultural mediums that comprise corn-starch, flour, or oatmeal, one may benefit thus by adding to the aforesaid mixture of bread and water one generous pinch of yeast for every slice of bread that one uses.

    One need only produce a sufficient quantity of cultural medium to form a layer of approximately 10 mm on the bottom of the container that one intends to use.

    [Hint: if the ratio of bread and water to Walter-worms is too high, the said cultural medium may liquefy within two weeks to the extent that the majority of the relevant colony of Walter-worms would be completely submerged. Since such an occurrence ought to be avoided, one may benefit from using no more than six slices of bread per suitably-sized container.]

    Subsequent to having poured a quantity of cultural medium into a container, one could place a starter-colony of Walter-worms on the surface of the relevant cultural medium using one’s fingers or such items as a debit-card, a dedicated teaspoon, or an ice-cream-stick.

    As a rule of thumb, one is advised to wash one’s hands subsequent to handling any organisms, including Walter-worms.


    When a colony of Walter-worms have expanded to the extent that masses that resemble quantities of liquid will have begun to form, one could commence with harvesting by scooping small quantities of the said masses and depositing the said quantities in one’s aquarium or aquaria. Alternatively or additionally, one could scrape off the sides of the relevant container small quantities of any Walter-worms that may have begun to ascend along the walls thereof.

    Depending on such considerations as temperature and the dimensions of the relevant container, one may only be able to commence with harvesting after a period of five to ten days.

    Daily Maintenance

    One is advised to ensure that the contents of each container remain moist. To the said end, one could use a spray-bottle to mist daily the contents of each container while taking care to avoid spraying as much water as would result in the formation of a layer of water. Additionally, one could refrain from removing the lid of any container for longer than is necessary so as to avoid facilitating the loss of moisture.

    Triweekly Maintenance

    For the purposes of maintaining the optimum health of a colony of Walter-worms and of avoiding some of the potential difficulties that are associated with aged cultural mediums, one could transfer on a triweekly basis the relevant colony to a clean container that contains a freshly prepared quantity of cultural medium.

    When transferring a colony of Walter-worms to a new container, one is advised to refrain, to the extent that is possible, from transferring aged cultural medium to a container that contains fresh cultural medium. To the said end, many Walter-worms will remain in a container subsequent to a transfer.

    Prior to disposing of the aged substrate and of the Walter-worms that remain in a container subsequent to a transfer, one could soak the said contents for approximately five minutes in water that has been heated to 100°C so as to avoid releasing live Walter-worms into one’s local ecosystem.


    One is advised to store one’s Walter-worms at room-temperature in dark cupboards.


    1. Robert G Piper (Editor) (1990). Yield Characteristics of the Free-Living Nematode Panagrellus redivivus in Different Culture Media. The Progressive Fish-Culturist. Volume 52. American Fisheries Society.

    Copyright © Kevin J W Mellors.​
    Cale24 likes this.
  2. Guest

  3. Cale24


    Oct 20, 2018
    Likes Received:
    Cape Town
    Hard to find 'em locally in CT, so I've only used microworms.
    nate likes this.
  4. A new day

    A new day Moderator

    Jun 13, 2019
    Likes Received:
    Cape Town
    Hi @Aquarist and welcome to TASA :thumbup:

    Great article, thanks!

    Pop over to New Members to introduce yourself then chime in on other threads and show us your tanks :thumbup:
  5. MariaS

    MariaS Moderator

    Apr 23, 2015
    Likes Received:
    Klipriver, Midvaal
    Hi @Aquarist

    Welcome to the forum

    Interesting article, thanks
    As @A new day said, we would love to hear a bit about you and your tanks!
  6. Nirvashen


    Sep 7, 2012
    Likes Received:
    hello and welcome great first post:thumbup:
  7. OP

    Aquarist Kevin

    Feb 5, 2021
    Likes Received:
    Pretoria, South Africa
    Thank you, everyone, for your compliments.

    I have posted an introduction.


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