Nile tilapia (Oreochromis niloticus) constitutes the maximum essential and financial fish species in Egypt representing 71.38 % of overall cultured fish in Africa and 1.54 % of overall cultured fish everywhere in the world. They compromise many vital amino acids, vitamins, poly saturated fatty acids, omega-3, vital minerals in addition to quantities of hint elements. Egypt is the third biggest tilapia generating country after China and Indonesia. The maximum crucial governorates in Egypt that produce 80 % of the farmed tilapia in Egypt are Kafr-Elsheikh, Behira and Sharkia. Aeromonas infection in fish causes world economic problems because of the high number of fish mortalities particularly in China and India .Aeromonas hydrophila (A. hydrophila) is one of the most important agents of the outbreaks in fresh water fish, in which skinulcers, hemorrhage and necrosis of the visceral organs are the major symptoms. Synonyms are bacterial hemorrhagic septicemia, septicemia, or pest. The application of medicinal plantsin aquaculture has been a new approach. The adequate use of antibiotics and other chemotherapeutics in fish culture criticized because of the potential improvement of antibiotic-resistant bacteria, environmental pollution and the accumulation of residues in fish tissue. Based on current information about the ecology, pathogenicity and epidemiology, of the Genus Aeromonas, we should assume that infection with aeromonad will remain a great health problem in the future. The ubiquitous distribution of Aeromonas infection and the increasing elderly population, to whom these bacteria are an opportunistic pathogen, will facilitate this problem.