Fish is the principal source of protein for people in many parts of the world, particularly in developing countries. While most fish are caught from nature, aquaculture or fish farming is now making a significant contribution to total fish production. More intensive conditions of aquaculture often result in a higher incidence of fish diseases and disorders. As in the first edition, the focus of this second edition is on protozoan and metazoan parasites that cause disease in fish. Significant changes to this second edition include the addition of 3 new chapters and 4 of the original chapters have new authors.

* Phylum Amoebozoa, D Zilberg, Ben Gurion University of the Negev, Israel and B L Munday, University of Tasmania, Australia; * Phylum Dinoflagellata, E J Noga and M G Levy, North Carolina State University, USA; * Diplomonadida (Phylum Parabasalia) and Kinetoplastida (Phylum Euglenozoa), P T K Woo; * Ichthyophthirius multifiliis and Cryptocaryon irritans (Phylum Ciliophora), H W Dickerson, University of Georgia, USA; * Trichodinidae and Other Ciliates (Phylum Ciliophora), L Basson and J Van As, University of the Free State, South Africa; * Phylum Apicomplexa, K Molnar, Veterinary Medical Research Institute, Hungary; * Phylum Microspora, I Dykova, Institute of Parasitology, Czech Republic; * Phylum Myxozoa, S W Feist and M Longshaw, CEFAS Weymouth Laboratory, UK; * Monogenea (Phylum Platyhelminthes), K Buchmann and J Bresciani, The Royal Veterinary and Agricultural University, Denmark; * Digenea (Phylum Platyhelminthes), I Paperna and R Dzikowski, Hebrew University of Jerusalem, Israel; * Cestoidea (Phylum Platyhelminthes), T A Dick, C Chambers and I Isinguzo, University of Manitoba, Canada; * Phylum Nematoda, K Molnar, K Buchmann and C Szekely, Veterinary Medical Institute, Hungary; * Phylum Acanthocephala, B B Nickol, University of Nebraska-Lincoln, USA; * Phylum Arthropoda, R J G Lester and C Hayward, The University of Queensland, Australia; * Phylum Annelida: Hirudinea as Vectors and Disease Agents, E M Burreson, The College of William and Mary, USA; * Fish-borne Parasitic Zoonoses, R C Ko, The University of Hong Kong, People's Republic of China; * Parasitic Diseases of Shellfish, S M Bower, Pacific Biological Station, Canada; * The Immune System of Fish, W B van Muiswinkel and B Vervoorn-Van Der Wal, Wageningen University, The Netherlands; * Immunocompetent Cells and Their Mediators in Finfish, B F Ardelli, McGill University, and P T K Woo; * Molecular Approaches and Techniques, T G Clark, Cornell University, USA.