I have been handling and feeding blackworms to tropical fish since about 1968. I was a young kid working at a fish store while going to Purdue University and we had been selling the red tubifex worm to the hobbyist for 1-2 years...and then all of a sudden there were these “monsters”. The black worm is not a black “red tubifex worm”. It is simply another type of worm that someone thought would be of some use in the hobby. Boy, talk about an understatement.

The red tubifex worm tended to spoil easily and really make a mess in the tank and the container in which they were kept. The black worms seemed not to be this tremendous mess so they were an instant success. Black worms are about twice as big as the tubifex worm but after a while you don’t seem to notice the difference and most people became less squeemish very quickly.

The discussion of the possibility of disease will be saved for a later article. Let it suffice for the moment that I have used them for some 30 years and can count on 2-3 fingers the number of fish I think I lost to these worms. So let’s find out how I treat them before I feed them to the fish.

I get the worms from the fish store in a bag...generally about a fist full but get what ever amount you wish. Put them in a long, low, flat container (see the picture)...and rinse the be-goobers out of them. The first day I’ll rinse them 5-6-7 times until the water coming off them is perfectly clear. I then put the container in the refrigerator and clean them the next day. I rinse them 4-5 times each time I get them out to clean them. I run the sprayer over them so that they “boil” in the stream of water. When the container is full of water I set it down until the worms all go to the bottom and then I pour the water out of the container. I do this every day for at least 4-5-6 days until the water at the first of

the cleaning is as clear as the last water I rinse them in.....it will happen. I usually have one container I am feeding from and one container I am cleaning. I have had good clean black worms last up to a month without feeding them...until I fed them all to the fish......they seemed perfectly clean and healthy the whole time.

Breeding: This is a reprinted article from the South Carolina Biological Supply House

“California blackworms can be cultured and easily maintained in a small aquarium or deep pan filled with 23 inches of spring water (or aged tap water). At room temperature in the laboratory, populations double in about 34 weeks or less. Using a disposable plastic pipette, transfer a few dozen, undamaged, healthy worms into the aquarium. Never attempt to handle or transfer worms
with forceps or hooks. They are easily injured by these instruments. Next, add enough strips of brown paper towel to just cover the bottom of the container. The towel serves as a fibrous substrate of decomposing material, both for the worms and for numerous microscopic organisms that may cohabit the culture, such as bacteria, protozoans, rotifers, and ostracods.

Add sinking fish-food pellets as the primary food source for this simple aquatic ecosystem. Start by adding one or two pellets. After a few days, add one or two more, but only if the others have been consumed. Do not overfeed, since decomposition of uneaten food may contaminate the aquarium and cause a mass die-off of worms. Worms are not harmed, however, by irregular feeding or long periods of starvation.

Replace water lost to evaporation by adding spring water (or distilled water). I recommend continuous, gentle aeration, and this becomes increasingly important as biological decomposition of the paper occurs and as the worm population increases.

As the paper towel disintegrates and waste residues accumulate, replace the culture water regularly (about every two weeks) by slowly decanting it down a drain. Be careful not to lose remaining paper and worms at the bottom. After rinsing the paper and worms again with spring water, and decanting, refill the aquarium to the original level and add new pieces of towel. I suggest the occasional "harvesting" of surplus worms; these can be used for classroom experiments, as live food for fish, or for starting duplicate cultures. I strongly advise the maintenance of at least one duplicate culture. If you follow these procedures, the worms reproduce continuously by asexual reproduction (fragmentation), and cultures may be sustained for years.”