This is the so-called bible for aquarium fish hobbyists! Use by many schools that teach fish diseases. This large book (232 pages) covers the most important fish diseases ,explained in an easy to understand content, discussed for each fish family with its typical disease.s All illustrated with 1000 color photographs of fish and pathogens with microscopic observation. Much info about possible treatments. The author Gerald Bassleer is well-known in the international aquarium industry due to his large experience and knowledge obtained by 40+ years work & research.