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Greater Seattle Aquarium Society

Worms in the Aquarium part one: Tubifex (not TubiFLEX!)

by Steve Ward

Don’t look now, but there are worms all around you. I’m calling this article Worms in the Aquarium Part One because the GSAS meeting starts in one hour and I’m going to have to do this off the top of my head.

Here we go:

There are two types of Tubificid worms (Phylum Annelida, Order Oligochaeta, Family Tubificidae) which are raised and sold as fish food.... the red Tubifex (Tubifex tubifex) which has been in the hobby for about 100 years, and the black Tubifex which is a similar species that is darker in color. The Amino acid profile of the proteins in Tubifex is very good, but the Fatty Acid profile is pretty bad. Therefore, fish fed Tubifex grow quickly but don’t show as much color as they do deformities. The black Tubifex is hardier, more resistant to desiccation, and less likely to cause disease in fish. Before the advent of frozen Bloodworms (not really a worm, I’ll talk about these later) Tubifex were routinely used as food for fish that refused flake food and when people wanted to condition their fish, that is, fatten them up for breeding. Some pet stores sell Tubifex as Live Bloodworms which is a misnomer because Bloodworms are the larvae of a type of fly. Because Tubifex feed on anaerobic bacteria they can cause intestinal disorders in fish (food poisoning, basically) and septicemia (which means blood-poisoning). Predatory Cichlids such as Oscars can become quite ill after eating Tubifex because they eat the worms regardless of whether the worms are live or severely decomposed. Cichlids from lake Malawi and lake Tanganyika crave these worms because they are a rare delicacy in those lakes. The consequence of feeding live Tubifex worms to African Cichlids is a disease known as Malawi Bloat which is a severe bacterial infection in the intestine (Malawi Cichlids have very long intestines because most of them are herbivores). Tubifex were once commonly collected in open sewers in Mexico because they thrive in polluted waters with high aeration and good circulation. These days, most Tubifex come from Worm Farmers or from trout or salmon hatcheries, where they are collected from the race-way effluent. At one time these worms were fed to small salmonids but this practice ended when it was discovered that the worms served as a carrier for the intermediate form of a sporozoan (Myxobolus) that is responsible for Whirling Disease. Yes, this disease does occur in some tropical fish.

Steve Ward works behind the counter at B&D Aquarium in West Seattle. He’s also one of GSAS’s longest-running active members.