The invention relates to a modular assembly (10, 20) for fry and other aquatic organisms comprising at least one support (11, 21) of materials forming reliefs, materials (9) forming reliefs liable to encourage the growth of the fry and aquatic organisms, said materials being arranged with the material support (11, 21) so as to define a zone in which the fry and aquatic organisms can live, and at least one protective structure (12, 22, 23) comprising mesh walls delimiting an empty volume, said protective structure being fixed removably to the material support (11, 21) and arranged therewith in such a way as to establish a protective zone protecting the living zone. The protective structure (12, 22, 23) thus constitutes a temporary structure of the modular assembly (10, 20) used only during the period of recruiting juveniles and postlarvae.
