Howlett's Battery on 5 and 6 December, firing 46 shells without being hit in return. The only damage sustained was from the muzzle blast of the right gun that forced the armor at the gun port out about and broke a number of bolts. Reassigned to the North Atlantic Blockading Squadron, the monitor arrived at Beaufort, North Carolina, accompanied by the sidewheel gunboat , on 15 December 1864, and took part in the attacks on Fort Fisher, North Carolina. In the first engagement on 24–25 December, Canonicus anchored at ranges from and fired 144 rounds, Lieutenant Commander George Belknap claiming to have dismounted two Confederate guns. The ship was hit four times, but suffered no casualties and no significant damage. On 13–15 January 1865, during the second attack, Canonicus fired 279 shells at the fort, most on the first day, again claiming to have dismounted two guns. She was hit at least 38 times in return but was only lightly damaged, and three crewmen were wounded. The ship's flag was twice shot away and replaced each time by Quartermaster Daniel D. Stevens. Stevens was later awarded the Medal of Honor for his actions. On 17 January 1865, Canonicus, towed by the steam sloop-of-war , was ordered to join the South Atlantic Blockading Squadron and arrived at Charleston, on 19 January. The following month, Canonicus and the monitors and captured a blockade runner that had run aground on Sullivan's Island, on the night of 18 February. The ship, towed by the steamer , together with Monadnock and other ships steamed to Havana, Cuba, in late May, in search of and arrived there after the ship had been turned over to the Spanish authorities by her captain. The two monitors were the first American ironclads to arrive at a foreign port. They returned to the United States, on 6 June. Canonicus arrived at the Philadelphia Navy Yard, on 25 June 1869, and was decommissioned five days later. The ship was renamed Scylla on 15 June 1869, but resumed her former name on 10 August 1869. She was recommissioned on 22 January 1872, and cruised the coastal waters of the Atlantic and Gulf of Mexico whenever she was in commission. Canonicus was finally decommissioned in 1877, at Pensacola, Florida. The elderly monitor was towed to Hampton Roads, Virginia, in mid-1907, as an exhibit during the Jamestown Exposition as the last survivor of the