HMS Sunfish was a Royal Navy S-class submarine which was launched on 30 September 1936 and fought in the Second World War. Sunfish is one of 12 boats named in the song Twelve Little S-Boats. She spent an eventful period with the Royal Navy on the outbreak of war, and was commanded for much of her career in the war by Lieutenant Commander J.E. Slaughter. In February 1940, she attacked U-14, but failed to sink her, and in April sank two German merchant ships, the Amasis and the Antares, and narrowly missed out on sinking the Hanau and an auxiliary patrol vessel.