Fidel Kalala (43), originally from the Congo, was also caught with cannabis herb hidden in his car outside his home in north Dublin. The court heard he was the "forwarding person" in Ireland for the drugs and at a low level in the operation.
Judge Mary Ellen Ring put the matter back to January next year for sentence and ordered a probation report be prepared.
Kalala, of Castlefield Woods, Clonsilla, pleaded guilty at Dublin Circuit Criminal Court to possession of cannabis for sale or supply at his home on March 4, 2009.
The court heard that customs officials intercepted a package which smelled strongly. On opening it, they discovered several fish which were stuffed with cannabis herb.
They organised for the package to be delivered to its intended address and when Kalala's wife accepted it, gardai got a search warrant for their home. They found the fish and also more cannabis in Kalala's car.
The total amount found was just over 4kg worth €50,000. Aileen Donnelly, defending, said Kalala was a good father to his five children.