Ichthyosporidium spp

From Fish

Ichthyosporidium spp, (Genera: Ichthyosporidiidae) was once believed to be a fungus, but is a microsporidian parasite[1][2] that infects the muscular and areolar tissue of the Neon Fish (Hyphessobrycon innesi). This disease, which is invariably fatal, should not be confused with Neon Tetra Disease in aquarium fish[3].

Life cycle

Ichthyosporidium is essentially histozoic and cytozoic. Nuclei of the host areolar tissue become hypertrophied, but those of the muscles are compressed or obliterated. Pressure effects prevent normal movements of the organs of the host.


  1. F. Nilsen (2000) Small subunit ribosomal DNA phylogeny of Microsporidia with particular reference to genera that infect fish. Journal of Parasitology 86(1):128-133
  2. Sprague, V. , J. J. Becnel , & E. I. Hazard . (1992) Taxonomy of the Phylum Microspora. Critical Reviews in Microbiology 18:285–395
  3. Porter, A & Vinall, HF (2009) A protozoan parasite (Ichthyosporidium spp) of the Neon fish Hypessobrycon innesi. Proceedings of the Zoological Society of London 126(3):397-402