"To take the animal out of here and to go on tour with it would not be good. The best for the animal would be to be cared for by someone who already has a couple of capuchin monkeys," said Karl-Heinz Joachim, head of the animal home currently hosting the animal.
"The monkey does not like being alone - it is like a person."
He told the Süddeutsche Zeitung newspaper the best solution would be to take the monkey, which is only 14 weeks old, away from Bieber, himself only 19.
"It is a wild animal which would normally live with its mother for a year. And Mally is only 14 weeks old. Whether Justin Bieber gets it back will at the end of the day be decided by the customs and the federal office for species protection. I am only looking after it."
Bieber has been pictured with the tiny monkey on his head, holding onto his hair - but now the animal, called Mally, is clutching a stuffed toy - an ersatz mother, said Joachim.
"The animal was separated from the mother far too early. According to our law, one would have to confiscate the monkey," he said.
Bieber has four weeks to produce papers showing the animal's provenance and health - it was his inability to do so that prompted customs officers to seize the monkey on Thursday after the pop star arrived in Munich for his German tour dates.
If Bieber fails to produce the correct paperwork, the animal will be made available for placement elsewhere, customs officers said.
When asked whether he had a message for Bieber, Joachim said, "Dear Mr Bieber: If you do collect your monkey from us, it would be very good if you were to employ someone to look after it and give it everything it needs. There must be money enough for this."