Harlequin was launched 3 June 1944 by Willamette Iron and Steel Works, Portland, Oregon; sponsored by Mrs. Mary M. Doig, whose husband and son were reported missing in action and who also had another son, a brother, and nine nephews in the Navy. She commissioned 28 September 1945. Reporting to San Pedro, California, for shakedown 19 October, Harlequin remained there until 29 November, when she sailed south, reaching New Orleans, Louisiana, 15 December. Harlequin sailed to Orange, Texas, 2 April 1946 and decommissioned there 27 May. While she remained in reserve, Harlequin was reclassified MSF-365 on 7 February 1955. Harlequin was struck from the Navy List on 1 May 1962, and later, on 2 October 1962, sold to Mexico.
The former Harlequin was acquired by the Mexican Navy in October 1962 and renamed ARM DM-20. From 1976–1978 she was disarmed and converted to an oceanographic research vessel; she was renamed ARM Oceanográfico (H02) around this same time. In 1993, she was renamed ARM General Pedro María Anaya (A08). Some time after April 1999, she was rearmed and converted to a school ship (Spanish; Castilian: barque escuela) and renamed ARM Aldabaran (BE02).
, Aldebaran remained in active service with the Mexican Navy. The vessel was later sunk to create an artificial reef. This reef is a popular dive spot for tourists.[1]