During last years the aquaculture production is growing thanks to its intensification (i.e.: growth promoters, use of antibiotics, and several other additives); obviously these practices create stressful conditions that cause problems related to diseases and deterioration of environmental conditions often occur and result in serious economic losses. The control of diseases using antibiotics has been questioned by acquisition of antibiotic resistance with a massive diffusion in the environment; so the use of probiotics (environmentally friendly) is an interesting alternative. Probiotics are used for: alternative measures to control the fish diseases, to promote health and finally formulate balanced diets for a better growth.