Liver diseases in tropical fish arise from diverse causes, but most of these can be understood by comparison with processes that have been better studied in their mammalian counterparts. The nature of the industry, particularly the methods of collection, handling, and transport of fish before their point-of-sale to the consumer, can introduce factors leading to hepatic disorders, especially hepatic necrosis. However, factors within the home hobbyist's aquarium also can be significant, especially for hepatic lipidosis and infectious conditions such as fish "tuberculosis" associated with Mycobacteria species.