The present invention pertains to a method for automatic sea lice monitoring in fish aquaculture, the method comprising submerging a camera (4) in a sea pen (300) comprising fish, using the camera to make an image of at least one of said fish, analysing the image to differentiate between individual sea lice present on the fish and the fish itself and assessing the number of sea lice present on the fish, wherein the camera is attached to a device (1, 10, 100) for guiding the salmon along an imaging track (5), the camera being directed to the track.