A floatable fish tank (100,101,102) comprising: a hull (10) having a lower part (10a) with side and bottom walls (11,12), the lower part (1 Oa) forming an enclosure (25) for fish； a deck (15) arranged at an upper part (10b) of the hull (10)； a central column (13) fixed within the hull (10), characterised in that the central column (13) is closed at its lower end section (13a) and extends from the bottom wall (12) to the deck (15). A fish farm (200) is described comprising a plurality of such floatable fish tanks (100, 101, 102).
