A fish tank 10 for use in aquaculture. The fish tank is formed at least in part in concrete. The fish tank includes a ballast-adjusting arrangement for raising and lowering the fish tank, an instrumentation arrangement or sensors for monitoring a region within the fish tank, a circulating arrangement for circulating and/or aerating water within the fish tank and a draining arrangement for draining the fish tank when its fish are to be harvested. The ballast-adjusting arrangement may be used to submerge the tank to prevent damage in rough weather. The ballast-adjusting arrangement may be provided as a plurality of separate tanks that may be individually adjusted to change the tilt and height of the fish tank. Also provided is a method of using a fish tank for aquaculture.
