The man, 24, was arrested at Hout Bay harbour in the early hours of Wednesday morning, said Sergeant Noloyiso Rwexana.
She said detectives had been hard at work following up leads.
Ivanov, 44, a husband and father of three, had been in the country on business and stayed in Hout Bay on a two-day break.
He was robbed and stabbed to death near East Fort, a popular tourist site on Chapman's Peak, on Saturday morning.
Community Crime Prevention (CCP), a local security response group that was on patrol, apprehended 23-year-old Sinaye Mposelwa and found a black backpack that was believed to have belonged to Ivanov. It emerged during court that Mposelwa had been out on parole at the time of the killing.
"On his clothes, and also his face, he was full of blood," prosecutor Nicky Konisi told the Wynberg Magistrate's Court on Monday.
Konisi said the blood was believed to be that of Ivanov as he was found with multiple stab wounds.
Almost 10 000 people had signed a petition by CCP, asking the court to deny Mposelwa bail.
Table Mountain Watch (TMW) has been vocal about its efforts to come up with a joint, agreed, integrated and acceptable solution to attacks in the park.
It declared the TMNP a "crime hot spot", and believed users were on their own when it came to their safety.
The second man was expected to appear on a murder charge in the Wynberg Magistrate's Court on Friday.
