A containment pen for finfish aquaculture, comprising a supporting structure, a net attached to the supporting structure and defining a containment volume for containing finfish, wherein the net comprises a plurality of removable net panels, wherein each of the removable net panels comprises a discrete piece of flexible netting attached along its perimeter to one or more substantially rigid members, and wherein the removable net panels are configured to be removable from the containment pen with the piece of flexible netting remaining attached to the substantially rigid members.