White Worms

Feeding

All aquarists have heard of the term "white worms", but interestingly not everyone has made this easily propagated, clean, appetising, live food available to their fish.

Scientific name: Family : Enchytraeidae, Generic Name : Enchytraeus
Common Name : White worms or enchytrae
Species : There are many species, and identification is not necessary as they are all good food for fish and cultured in the same fashion.
Description : Segmented round worms about 25mm in length and closely related to the common earthworm. Close examination with a magnifier will reveal bristles on the outside of the body, movements of the gut and passage of food from the mouth (anterior) to the anal opening (posterior). The colour is commonly milky white, hence the name. Diameter is between 0.7mm and 1.5mm. Each individual carries organs of both sexes and reproduction is effected by cross fertilisation similar to the earthworm. The reproduction process produces eggs in a transparent cocoon. White worms do not have a thick cuticle like other worms. Its thin cuticle permits the diffusion of water into and out of its body. Consequently, without 100% soil humidity, the worms dry out, and die.

Cultivation : White worms need high moisture levels, large soil surfaces, darkness, low temperatures and protection from enemies.

Containers used for culturing white worms have included unpainted wooden boxes (175mm x 250mm x 75mm High) [this is the best], plastic boxes, flower pots, concrete boxes, dish pans, glass culture dishes, tin cans, garbage cans, styrofoam shipping boxes. Size is not too important, as long as it fits your plans. Consideration should be given to keeping out insects (e.g. ants) and vermin that will attempt to enter the container for food and breeding, so a tight fitting lid is appropriate.

It is important that the moisture of the medium be retained by the use of a tight fitting lid. Above 22^oC, the worms die, while at 1^oC, they will not breed, and at 0^oC they will die. Optimum temperature is 18^oC (65^oF) and their reproduction rate decreases in direct proportional to the departure from this optimum. In a small bar fridge, or, with your partners permission, in the bottom of your family refrigerator are ideal locations for our sub-tropical climate. If the bar fridge is set to its warmest setting the worms will flourish. In my case this turns out to be 15^oC. The closed and cool environment of the refrigerator also removes most of the problems associated with mites etc.

The soil should not cake or become tightly packed (must allow air flow), should not readily turn sour, should hold sufficient moisture without getting soggy, should allow the white worms to move about freely, and must contain no fertilisers or fungicides. I am aware of orchard mix, peat moss, wheat hulls, and gravel being adopted for the soil medium. I personally use horse manure (only). One problem with a refrigerator is that the soil can become "dry" around the edges of the wooden container, and I do moisten this area by the addition of water.

There is a wide variety of foods to feed the white worms. Bread, rolled oats, mashed potatoes, baby foods, cottage cheese and so on. It is important to ensure that all the food is eaten and that the soil is not soured, or else the worms will attempt to move house. Uneaten food should be removed. Do not add additional food until all previous food has been eaten or removed. Normally the food is placed on the surface of the soil in a small depression. On top of this is placed a sheet of glass. The worms will collect and eat under the glass where the humidity and moisture is best. Glass allows us to see the worms, but any cover will do on the surface of the soil. I use white bread soaked in water. One scientific study found that bread crumbs moistened with water gave the best growth results.

When cultivated properly, the worms form large colonies. At this stage, it is a simple task to simply take clumps of worms from the culture, virtually without any soil or contaminants.

Feeding to the fishes : White worms store fats as solids rather than oils. Because fish do not digest solid fats efficiently, white worms are not recommended as a daily staple food. Constipation is a real possibility. They are ideal for conditioning fish prior to spawning, for stressed and weakened fish, for fish recovering from disease or for young fast-growing fish.

Feed only a few at a time to the fish. The plastic tubifex worm feeder is appropriate for feeding white worms to your fish in a slow and proportioned manner. If you have no gravel in your aquarium you can just drop the worms into the aquarium where they will move conspicuously on the glass bottom, thus attracting the fish. I place my "clumps" in a glass of water and "squirt" worms and water into each aquarium. Chlorine in tap water will kill these worms quite quickly. In an aquarium I have seen them still wriggling after 2 days.

Egg capsules also make an excellent food for baby fish. In a well managed culture the surface of the soil is almost encrusted with white globules which can be skimmed off with a knife blade. I have never had the experience.

Close relatives : Grindal Worm (dwarf white worm) approx. 13mm.

Source of worms : Most white worms are available in the wild, outdoors, and may be collected from soils that do not dry out, and where there is remains of vegetation. This seems to suggest the deeper layers, but not always. Their distribution is patchy. If the soil is acidic the worms become extremely scarce. It is easier to get a supply from a friend or your local aquarium retailer. I had a situation in my yard where after heavy flooding rain a white patch covering some half a square metre and a centimetre thick appeared in my lawn - white worms. I have a habit of cleaning my culture boxes in the garden nearby.

Maintenance : Do not disturb the culture unnecessarily. It is disruptive to the activities of the worms.

After about 6-9 months, biological processes cause the soil to become acidic, and a significant decrease in the reproduction of the worms is noted. The soil texture at this time has a muddy type appearance. Collect the top layer, where most of the worms reside and dispose of the rest. Replace the disposed soil and add the collected worms and soil, and in no time the production line is back in action. Simple.