Maintenance device of at least one organism whose natural environment is an aquatic environment, which includes at least: a container intended to contain said organism, said container being provided with side walls and with a lid to cover at least partially an upper surface of the container , said container presenting a water inlet and outlet, respectively, intended to receive and give a flow of water through said container, at least one of said side walls comprising at least one hole forming a water outlet of the container, presenting said lid an outer surface that includes a cavity suitable for receiving a water flow and directing said flow towards at least one hole included in said lid that forms the water inlet of the container, characterized in that the side walls of said container are inclined so that two facing side walls comprising at least one hole that conforms a water outlet of the container widens forming a truncated "V", the inclination being such that the bottom of a maintenance device can fit into the cavity of the lid of an immediately lower maintenance device, with a play between the side walls of the container of said upper maintenance device and edges of the lid of said lower device.Dispositivo de mantenimiento de al menos un organismo cuyo medio natural es un medio acuático, que incluye al menos: un recipiente destinado a contener dicho organismo, estando dicho recipiente provisto de paredes laterales y con una tapa para recubrir al menos parcialmente una superficie superior del recipiente, presentando dicho recipiente una entrada y una salida de agua, respectivamente, destinadas a recibir y a dar un flujo de agua que atraviesa dicho recipiente, comprendiendo al menos una de dichas paredes laterales al menos un orificio que conforma una salida de agua del recipiente, presentando dicha tapa una superficie exterior que incluye una cavidad apta para recibir un flujo de agua y dirigir dicho flujo hacia al menos un orificio incluido en dicha tapa que
