Tubifex fish health warning

Scientists at the Institute of Biology of the University of Munich, in Germany, acquired live 'tubifex' worms from a number of aquarium shops in the city and examined them to discover if they were infected with parasites. Not only did they find that nearly all carried parasites, but that these belonged to as many as twelve separate species. All twelve were found to be actinosporeans: ciliated protozoan parasites (single-celled parasites that swim using cilia or minuscule hair-like or whip-like structures), which are capable of infecting invertebrates and lower vertebrates. They further discovered that the twelve belonged to four separate types of actinosporeans. These parasites spend at least part of their life cycle inside their host, which in this case are 'tubifex' worms, subsequently spending a free-swimming stage in the water, during which they find a new host, e.g. a fish, in which they reproduce and die.This, of course, is bad news for those who feed live 'tubifex' worms to their fish - whether at commercial establishments or in home aquaria - since it means that the standard advice of keeping 'tubifex' worms under running water to cleanse them cannot get rid of the internal parasites. I have no information on whether the 'tubifex'-cleaning solutions that were once available (and which may still be in some countries) are indeed capable of disinfecting live 'tubifex' worms completely, so I restrict my comment purely to the water treatment of the worms. Commercial preparations of both frozen and deep-frozen 'tubifex' are a different matter altogether, as they are subjected to stringent disinfection treatments and are safe to use.Live 'tubifex' are potentially so dangerous because they are frequently collected from mudflats that are contaminated with sewage. However, they have always been popular because of their nutritional value, wide availability and low cost. The Munich study appears to be the first one to show the extent of the threat, though, and it could well mark the beginning of the end for the tradition of feeding live 'tubifex' collected from such environments. John Dawes
The term tubifex is quoted in inverted commas because it embraces several species of tubificid worms (family Tubificidae, class Oligochaeta), only one of which is a Tubifex species, i.e. Tubifex tubifex, the red tubifex or San Juan worm.The full report on which this item is based is: Hallett S.L., Atkinson S.D., Erseus C. and El-Matbouli M. - Dissemination of triactinomyxons…