We have had 2 sisters for nearly 3 years and tonight I found melody passed away in there cage. My daughter was heartbroken. We do all the right things and look after them so unsure what happened. She was eating and moving usual yesterday and now today......... I'm now afraid for her sister twinkle. I hear tales of they can't live long without a partner then I read introducing new partners is bad due to fighting. It still early but I worry over twinkle as I was expecting them to last longer. Is it ok to introduceher to a new buddy and if yes does it have to be a similar age?