The most important, but also interesting disease of meagre is a condition called Systemic Granulomatosis, which affects almost 100% of cultured populations. The disease is characterized by multiple systemic visceral granulomas that manifest progressively as calcified and necrotic organs. The aetiology is unknown, but there is evidence it may be a metabolic disorder, and similar to systemic granulomas observed in cultured fish species such as gilthead sea bream, rainbow trout and turbot. In all cases the development of the disease has been associated with a nutritional imbalance (phosphorus levels, vitamin C deficiency, etc) or inadequacy (plant ingredients, tyrosine, etc). Systemic Granulomatosis is not associated with high mortalities, however, both prevalence and intensity are so high that this disease ranks as one of the major bottlenecks of further expansion of meagre production. The disease may lead to reduced growth and physiological performance during grow-out and, in addition, it affects the final product, making it unacceptable to the consumer. DIVERSIFY will study the development of the disease under different feeding/nutritional regimes, in order to investigate the underlying causes and to reduce its incidence in aquaculture. Since there is evidence that the cause is related to nutrition, the variety of feeding trials foreseen in these studies will provide a thorough insight on the aetiology of the disease.