Provided is a system for centralized water monitoring of a fish farm. the system including a plurality of fish tanks divided into a first and a second subgroup; and a first sample conduit only connected to the first of the subgroups through a first set of pipe connections, and a second sample conduit connected only to the second of the subgroups through a second set of pipe connections; each one of the pipe connections being connected to only one fish tank; the pipe connections being configured for water sampling from a selected fish tank of the first subgroup into the first sample conduit and from a selected fish tank from the second subgroup into the second sample conduit. Water samples are received by a first and second sensor system from the first and second sample conduits for simultaneous measurements of the samples by the sensor system.