A multigonal knock-down polyethylene floating net cage system comprising a number of polyethylene floating device (1) forming multigonal floating net cage, which function as main structure and the net cage floater, a number of polyethylene inner membranes (3b) attached on each of the inner ends of said floating device (1) to ensure said floating device (1) will not leak, a number of polyethylene outer membranes (3) attached on each ot the outer ends of said floating device (1) to prevent water from coming into the floating device space (1) and also as section for connection (6a) to joint components (2) between one floating device with other floating devices, a number of joint components (2) which connects each ends of polyethylene floating device (1) so as to form a multigonal floating net cage opening (A), a number of bolts/nuts (7a, 7b) which connects/binds each ends of polyethylene floating device (6a) to said joint components (2), a number of tracks (5) installed on the upper side of polyethylene floating device (1) as walkway above the floating net cage, a number of fence bars (6) installed on net hook (4), a number of polyethylene net hook rings (4, 4a) and net hooks (4b) attached to each of said polyethylene floating device (1). Said polyethylene floating device (1) is equipped with at least two net hook rings (4) strongly attached to the outer side of said polyethylene floating device (1).Linvention concerne un système de cage flottante en filet de polyéthylène démontable multigonale comprenant un certain nombre de dispositifs flottants en polyéthylène (1) formant une cage flottante en filet multigonale, faisant office de structure principale et le flotteur de cage en filet, un certain nombre de membranes internes en polyéthylène (3b) attachées à chacune des extrémités internes dudit dispositif flottant (1) pour assurer que ledit dispositif flottant (1) ne fuira pas, un certain nombre de membranes externes en polyéthylène (3) attachées à chacune des extrémit