Biodegradable and nutritionally attractive composition comprising biocidal or antibiotic compounds and/or microbes having bio-adhesion and controlled buoyancy properties are selectively fed to an aquatic organism in open or closed water-bodies, and bioactive components are released upon contact with mucosal tissues such as gill, skin or along the digestive tract of the selected aquatic organism.COMPOSICION PARA APLICAR UN AGENTE BIOACTIVO EN AMBIENTE ACUATICO, QUE COMPRENDE: AGENTE BIOACTIVO, POLIMERO ADHESIVO, COMPUESTO REGULADOR DE DENSIDAD Y NUTRIENTE: METODO PARA PRODUCIR LA COMPOSICION Y METODO PARA CONTROLAR ORGANISMOS INVASIVOS EN UN AMBIENTE ACUATICO QUE COMPRENDE EL USO DE LA COMPOSICION.