We suggest a project aimed in increase the knowledge of the fish community in Doñana Nacional Park through systematic surveys carried on the pools of Caracoles estate and in lucios in the Oriental marshland sector. We treat to define an actualised analysis of the fish community in the proposed area. The specific objectives are to analyze fish species distribution, biomass, abundance and size structure in the Oriental sector and Caracoles estate pools and determine the conservation status of the fish community in this area attending to community composition index.