In-vivo fluid monitoring devices and methods are disclosed herein. An example device is configured for patients which monitors increases and decreases of fluid retention in patients with various clinical conditions such as heart and renal failure pre-operation and post operation thus allowing physicians to more accurately detect said fluid retention gains through a mechanism directly or indirectly connected to circulatory stocking which act as a conduit to detect said fluid changes through skin electrolysis and alterations respective to fluid changes directly corresponding with galvanic skin response measurement changes.