[Xuli]

Hi everyone!
So my sister has recently bought 2 boys from P@H and I have some questions and concerns.
I've been reading about pairs falling out and becoming territorial. They were in the same tank so I'm presuming they are from the same litter. It would be a shame if they fell out. How common is this?
They are in a petstore plastic cage for now. She has bought the Barney cage for them 100x50, is this cage too big? I was reading that there should be no platforms? She's ordered 2 of everything and she is making some lollipop stick crafts from youtube.
What about diet? Are they prone to diabetes?
I'm just a little worried she's wasted a lot of money trying to get a nice setup and give them the best. Advice would be much appreciated