Tubifex tubifex

Tubifex tubifex, also called the sludge worm, is a species of tubificid segmented worm that inhabits the sediments of lakes and rivers on several continents. T. tubifex probably includes several species, but distinguishing between them is difficult because reproductive organs, commonly used in species identification, are resorbed after mating, and because external characteristics of the worm vary with changes in salinity. These worms ingest sediments and gain nutrition by selectively digesting bacteria and absorbing molecules through the body wall. The worms can survive without oxygen for months, and can survive in areas so heavily polluted with organic matter that almost no other species can endure. By forming a protective cyst and lowering its metabolic rate, T. tubifex can survive drought and food shortage. Encystment may also function in dispersal of the worm.

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Uses

Ecologically, it is important as a source of food for leeches, crustaceans, insects, and fishes. Tubifex are sold to aquarists as fish-food in both live and freeze dried, pelletised forms. These worms are relatively easy to culture, but it takes a month or more to get a culture going to the point that it is ready to harvest.

Warnings

Tubifex usually contaminate tank water very easily and are not recommended.

It is most economically important to humans as a host of Myxobolus cerebralis, which causes disease in fish stocks. No other worms are known to harbor this parasite. Care should be taken when feeding Tubifex to aquarium fish.

References

• Gilbert, M. A. & Granath, W.O. Jr. (2003). Whirling disease and salmonid fish: life cycle, biology, and disease. Journal of Parasitology, 89(4), pp. 658–667
• Tubifex tubifex (TSN 68623). Integrated Taxonomic Information System. Accessed on 22 May 2007.