A monkey had to be put down on medical advice after her owners failed to care for her.
Precious – a Geoffroy’s marmoset – was euthanised due to the severity of her condition.
RSPCA Cymru said the couple had not researched how to care for a marmoset before purchasing her.
Laura Pittman and Jonathan Leighton Phillips from Ferndale, Rhondda Cynon Taf, were sentenced at Merthyr Tydfil Magistrates Court on Thursday after pleading guilty to two offences under the Animal Welfare Act.
They were disqualified from keeping animals for 10 years, fined £350 each and ordered to pay associated costs.
Phillips received a 12-month community order and a 10-day rehabilitation activity requirement.
A vet who examined Precious believed she was not provided with a suitable diet.
The RSPCA said radiographic findings were consistent with “severe metabolic bone disease”.
The disease develops when an animal has a deficiency of calcium and/or vitamin D3.
In mitigation, it was heard both defendants were remorseful and had been well-intentioned.
Speaking after the sentencing, the RSPCA’s head of wildlife, Dr Ros Clubb, said it was a “heartbreaking case”.
“Precious will undoubtedly have suffered horribly,” she added.
“Sadly we fear there are many more marmosets like Precious suffering behind closed doors because people do not know how to look after these animals properly and, as well as causing suffering to the animals, the owners risk falling foul of the law.”
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Charities such as the RSPCA have been calling for a ban on keeping primates as pets.
The UK government launched a consultation on proposals for a ban earlier this year.
Currently, people have to obtain a licence in order to keep them.
Dr Clubb said the animals had “specific needs” which can mean an “extreme” level of suffering.
“They are wild animals that do not belong in people’s homes,” she added.
