Mediterranean Sea is on the verge of a major change. Climate change, global warming of seawater, urbanization of the coasts, development of tourism and industrial facilities around the coastline and related anthropogenic effects have started to create an impact in our environment. These changes appear daily basis on TV around the globe in different forms as, hurricanes, tornados, floods, forest fires, coral bleaching, mass fish migrations and major shift in ecosystems. Some of these changes show itself in the Mediterranean coastline where the relationship of the men with the sea and fish first started. Since its construction in 1869, there have been a long list of tropical alien species that crossed the Suez Channel and settled in the Mediterranean waters in the last 150 years. These organisms were called Lesepsians referring to the name of Suez Channel developer, Ferdinand de Lesseps and they are equipped with extraordinary abilities cause tremendous damage to fisheries, reproduce promptly and prey on defenseless local endemic organisms. These invasive species cause an unprecedented impact on fragile habitats and the future of Mediterranean ecosystems is threatened by an army of organisms.