After being ejected from Carthage, Gelimer set up at Bulla Regia in Numidia, about 100 miles to the west of Carthage (at what is now the western border of modern Tunisia). He knew that in his current state he would not be able to face Belisarius's forces, so he sent messengers to his brother Tzazo who was currently campaigning in Sardinia. When he received the message, Tzazo set about returning to Africa to join Gelimer.
Meanwhile Gelimer also attempted to divide the forces helping Belisarius. He offered rewards to the local Punic and Berber tribes for every Roman head they could bring, and sent agents to Carthage to attempt to have Belisarius's Hun mercenaries – vital to his success at Ad Decimum – to betray him.
Tzazo and his army joined Gelimer early in December, at which point Gelimer felt his forces were strong enough to take the offensive. With the two brothers at the head of the army, the Vandal force paused on the way to Carthage to destroy the great aqueduct which supplied the city with most of its water.
Belisarius had fortified the city in the twelve weeks since Ad Decimum, but knew about Gelimer's agents and could no longer trust the Huns in his forces. Instead of waiting for a possible treachery during a siege, he formed up his army and marched out with the cavalry at the front, and the Huns at the rear of the column.
The two forces met outside Carthage and the Roman cavalry immediately charged the Vandal lines, reforming and attacking two more times. During the third charge Tzazo was killed within sight of Gelimer. As had happened at Ad Decimum, Gelimer lost heart. The Vandal lines began to retreat, and soon were in rout. Gelimer fled back into Numidia with what remained of his army, losing over 3,000 men killed or taken prisoner. Belisarius then marched on the city of Hippo Regius, which opened its gates to him.
Gelimer realized that his kingdom was lost, and attempted to flee to Spain where some Vandals still remained, not having followed the main forces when they crossed into North Africa years earlier. However the Romans heard of his plans and intercepted him. He was forced to adbandon his belongings and take refuge in the mountains of Tunis with the Berbers. The next year he was found and surrounded by Roman forces led by Pharas the Herulian. At first he refused to surrender, even after promises of being allowed to rule. After a particularily nasty winter, he eventually gave up and surrendered to Belisarius. The Vandal Kingdom ended, their provinces in Sardinia, Corsica and the Balearic Islands came under the control of Justinian.