I purchased a bonsai tree about 2 years ago and it has been doing quite well. I moved into a new condo a few months ago and brought the tree with me. It’s a west facing exposure room so it receives plenty of light, it grew quickly in the first month and so repotted it into a larger pot. I went on holidays for a week and while it received some natural light it was less than normal. I came back from holidays to find a stem had sprouted from it with leaves significantly larger than the rest of the plant. I have reviewed the species types on the website and cannot determine what kind of species that I have. I also would like some guidance as to why this large stem sprouted and whether I should prune it?

welcome to the empire.

My crystal ball is broken today. Do you have pictures instead?

My crystall ball still works

it is a ficus ginseng and has little to nothing to do with bonsai. It is one type of ficus grafted on the (ugly ) roots of another type of ficus. The shoot that sprouted comes from the "old" root of the ficus. Just cut it off.
Treat it as every other houseplant.