Zarabi joins from French side Gueugnon and can play at centre-back but is primed to fill David Murphy's boots at left back.
Nish, a life-long Hibs fan, has already scored twice against the Easter Road side this season but won't have the opportunity to open his account in Sunday's cup-tie having played â" and scored â" in Kilmarnock's Scottish Cup victory over Airdrie on Monday night.
It was in this game that Paatelainen became convinced of the player's worth.
"I hadn't seen him for a few years and wanted to see him play," said Paatelainen. "He was a name that was put straight to me when I came in but I couldn't decide because I wanted to see the player. I knew he was a tall centre-forward who scores goals but after seeing him I decided he is a player who can hopefully help us. I don't want to make blind signings."
Hibs, however, proved unwilling to increase an offer made to Malmo for Johansson. The bid, believed to be in the region of £150,000, was dismissed as too low by the Swedish club.