tu·bi·fex 
(tbə-fĕks′, ty-)
(tbə-fĕks′, ty-)n. pl. tubifex or tu·bi·fex·es
Any of various small slender reddish freshwater worms of the genus Tubifex, often used as food for tropical aquarium fish.
[New Latin Tubifex, genus name : Latin tubus, tube + Latin -fex, maker; see dhē- in the Appendix of Indo-European roots.]