An apparatus 10 suitable for growing crustaceans comprises a tank 12 of generally circular cross-section for containing water, a chamber 30 below the tank, a duct 36 extending from the chamber to a position near the top of the tank, and means to re-circulate water through the duct and the tank. Two separate re-circulation means may be provided. One of the means may comprise a biofilter (58, figure 2). A plurality of trays 40, defining compartments 46 to accommodate the crustaceans and having perforations 42 in their base, may be provided. Also disclosed is a method of growing crustaceans comprising the steps of circulating water through a biofilter for a period of time and circulating water without passing though the biofilter while providing the crustaceans with food, followed by repeating the steps.
