The present invention relates to a shelter for aquatic biodiversity and mainly for fish life, including a chamber (1e) defining an inner space and including an inlet defined by sides that define a perimeter having a width L1. Said shelter is characterized in that said inlet includes columns (4f, 4b) which are parallel to one another, each one extending from one first side of the perimeter of the inlet to a free end of each column, and which are arranged on an outer line (4f) and on an inner line (4b) that are substantially parallel to one another and distributed such as to be staggered over the entire width L1 of the inlet. Said shelter is also characterized in that each column has a length such that the free end thereof said column is spaced apart, by a distance h of 30 to 100 mm, from one side opposite the first side, and in that each column (4f) arranged on the outer line is separated from the nearest columns (4b) arranged on the inner line, by a distance d_min, of 10 to 200 mm. Assembling a plurality of such shelters (1) includes placing said shelters side by side, the roof (2) of one being substantially at the same level as the roof (2) of the other, and such that said shelters are separated from one another by a space smaller than 20 mm between the two roofs (2).
