This study describes briefly the intensive system production of sea-bass and sea-bream in tanks in Tunisia. We have taken the example of the Aquaculture Society in the South of Tunisia (A.S.T), the oldest and most important unit of production in Tunisia. This society practises the rearing in floating cages, it has also ensured a quarter of its production in small and big tanks since 1992. In 1993 it began to produce the sea-bream with the sea-bass. The results recorded in the A.S.T recognize that sea-bream production is less profitable than sea-bass. Profitability is hindered by the initial number of fry and sale price. This unit still needs to improve the fishing rate, selling the big fish at a better price and reducing the number of fry needed for production.