A gastrostomy device (100) comprises a gastrostomy tube (200) having a retainer lumen (235) extending between a proximal part and a distal part of the tube (200); and an inflatable retaining element (300) coupled to the tube (200) at the distal part. An interior space of the retaining element (300) is in fluid communication with the retainer lumen (300). The gastrostomy device (100) also comprises an indicator (410) being in fluid communication with the retainer lumen (235) at the proximal part of the tube (200). The indicator (410) is configured for indicating a pressure in the retaining element (300) continuously within a range from a pressure corresponding to an empty retaining element (300) to an optimal pressure for the inflated retaining element (300).