Answer based on context:

In January 1499, Kemal Res set sail from Constantinople with a force of 10 galleys and 4 other types of ships, and in July 1499 met with the huge Ottoman fleet and took over its command in order to wage a large-scale war against the Republic of Venice. The Ottoman fleet consisted of 67 galleys, 20 galliots and about 200 smaller vessels. In August 1499, Kemal Reis defeated the Venetian navy under the command of Antonio Grimani at the Battle of Zonchio . It was the first naval battle in history with cannons used on ships, and took place on four separate days: on August 12, 20, 22 and 25, 1499. After reaching the Ionian Sea with the large Ottoman fleet, Kemal Reis encountered the Venetian fleet of 47 galleys, 17 galliots and about 100 smaller vessels under the command of Antonio Grimani near Cape Zonchio and won an important victory. During the battle, Kemal Reis sank the galley of Andrea Loredan, a member of the influential Loredan family of Venice. Antonio Grimani was arrested on 29 September but was eventually released. Grimani later became the Doge of Venice in 1521. The Ottoman Sultan Bayezid II gifted 10 of the captured Venetian galleys to Kemal Reis, who stationed his fleet at the island of Cefalonia between October and December 1499. Ottoman incursions into inland Dalmatia also started in 1499, under command of Isa Pasha and Feriz Beg.

When was the second day of fighting in the Battle of Zonchio?
1499-August-20