Process for reconditioning a hermetic package (12) containing water (14P) and at least one alive aquatic animal (16), in particular intended for aquariums, the aim being to extend the maximum duration of transportation while keeping the animal alive, which includes the following steps: (a) opening the package (12) to access the water (14P) contained in it since the initial packing; (b) replacing all or some of the polluted transportation water (14P) with an unpolluted reconditioning water (26) prepared in such a way as to present physical and chemical parameters analogous to those of the polluted water (14P), and in particular at least a substantially identical pH value; (c) re-closing the package (12) in a leaktight manner in order to permit a further stage of transportation.