On July 11, Lieutenant Nikolaos Tsotakos (Captain Germas) arrived at Vogatsiko with his armed corps of 40 men. Northeast of Vogatsiko, near the church of Agios Georgios, the armed corps of Captain Germas met that of Gregory Falireas (Captain Zakas). On the same night (July 12), strong Ottoman forces entered the villages of Vogatsiko, Losnitsa (now Germas) and Kostarazi. The Ottoman soldiers advanced to the surrounding hills and encircled the Macedonian troops camped in the mountains.

The head of the Vogatsiko committee, priest Papademos, had warned the Greek chieftains of the coming Ottoman forces and suggested that they hide in a ravine leading from the monastery of St. Nicholas Tsirilovo to Losnitsa. So, the Macedonian fighters spent the first night in a cave, and the next night they moved to the "Kalogeriko" ravine, a position known to the armed forces, especially to Captain Zaka's group.

However, the Ottoman army, fully aware of the existence of the armed corps of the Greek Macedonian bands in the area, surrounded the Kalogeriko ravine and began the attack in the early hours of July 16. About 150 Ottoman soldiers attacked the Macedonian soldiers from all directions. During the battle, only a few Macedonian fighters managed to escape the fierce pursuit. A total of 11 were captured, while Captain Germas and his second in command, Staff Sergeant Vasilios Tsibidaros (Captain Tsibidas), as well as 21 other Macedonian fighters were killed by Ottoman fire. Despite being wounded, Captain Zakas managed to escape through the ravine.

In honor of Lieutenant Nikolaos Tsotakos, the Greek state renamed the village of Losnitsa to Germas by presidential decree of July 17, 1928 (Official Gazette 156, Vol. A, 08.08.1928).