White Worms

White worms are similar to earth worms, but reach a maximum length of about 1” and are colored white.  They are a great conditioning food for aquarium fish in the 1"-4" range. I no longer buy tubifex or black worms because of problems with parasites. I use white womrs instead. They are reasonably easy to raise if you can supply the right conditions.   

The right conditions are cool temperatures and the proper amount of moisture.   I have found the worms are best when the temperature is below 70F.  If the temperature rises above 80F you run the risk of losing the culture.   

Too keep them cool, I put my worm box in a cool, dark location right on the basement floor.  During the winter the temperature of the soil gets down to about 60F, and the worms do great. During summer hot spells it reaches the upper 70’s, and the worms do not do as well.

Close up of white worms. The silver disk is a dime.

The other critical condition is moisture.  Too little moisture and the worms dry out, and too much you end up with stinking, slimy mess.  The culture medium should be moist, and you should be able to form a ball in your hand, but it should not drip if you squeeze the ball.  

Many people raise their white worms in plastic containers. I found plastic containers make it difficult too keep the moisture at the proper level. Add too much water and you will kill the worms.  A far better solution is a wood worm box.   

My worm box is made of 1/2” thick pine boards. I would recommend against plywood.  Mine  measures about 6” X 18” X 5” high.  The wood tends to absorb excess moisture and release it back into the soil if it dries out.  The cracks at the joints will drain water if you add too much. Another advantage of placing it right on the cement basement floor is leakage does not cause that much of a mess.   

A glass cover with a piece of wood glued to it with silicon cement completes the worm box.  The cover helps prevent the culture medium from drying out.  

The medium I use for white worms is a 50-50 combination of potting soil and peat moss. There is about a 3” layer in the box.

Wood white worm box.  The wood helps to regulate the moisture of the culture medium. The glass cover is not in the picture.

White worms are not picky about food. Some of the things I regularly use are left over bread, Cheerios cereal, and dry cat food. Each has its own pluses and minuses. Bread is inexpensive.  Cheerios make harvesting easier, and cat food has more protein and the worms tend to reproduce faster. Bread and Cheerios also have preservatives which tend to reduce molding.  

Food should be moist when added to the culture. You can put it on the surface or bury it.  In general burying it is best. The worms like to be under the surface, and it is less likely to get moldy.  If you put the Cheerios on the surface, the worms will tend to form balls around them, which makes harvesting easy. 

Once you have your worm box ready, you need to get a starter culture.  Ask around at aquarium clubs. Chances are at least a few of the members who breed a lot of fish will have them.   

Place the worms at one end and add a small amount of food.  Check ever other day and if the food is gone add more. If the food is still there after a few days, back off on the amount you feed. The food should disappear in 2-3 days. At the start of your culture you will want to feed in the same area. As the culture grows you can increase the amount of food and spread it out more.  

A new culture will be ready for harvesting in about 2 months.  The worms will tend to form balls around the food. You can gently dig into the culture with a plastic spoon to find the balls if you bury the food. I use a large tweezers to pick out the worms. If there is only a small amount of dirt you can feed the worms directly. Otherwise put them in a small container of water and the worms will form small balls more or less free of the medium.  

The culture medium will start to sour over time. This happens faster if you use high protein foods like dry dog or cat food. You can sub-culture the worms, but since it takes a long time to really get a culture going it is better to replace the medium a bit at a time.  

My box is long and narrow. About every 3-4 months I put a cover that is only about 2/3 the length of the box. For several weeks I only feed and water the front and middle 2/3 of the box. The worms will migrate out of the back towards the food and moisture.  After a few weeks there will be few or no worms at the back.  

At that point scoop out the dry medium at the back. Push the remaining medium from the front to the back, and put in fresh, damp new medium in the front and start feeding at that end.  This method minimizes the disruption of the culture.  

White worms are high in fat, and many aquarists recommend against feeding them more than a couple of times a week. I try to follow this rule except when conditioning fish for breeding.   I stopped using black worms, tubifex worms, and similar aquatic worms because of problems with introducing parasites and disease.  I find the white worms are the best conditioning food I feed.