I was recently offered condolences when someone found out about the unfortunate fate that befell my Bonsai plant. There's a small update!
A little over a month ago, Veronica and I went to a terrarium workshop and put together a little home for a little ficus. They're very hardy.
I picked everything out down to the colours of the sand layers and we carefully placed and aligned everything. It's not just pretty, but everything has a function. For example, the moss tells you when when it's time to add (distilled!) water, the large rocks can provide a surface for that water to evaporate (rather than get absorbed by the moss). We also added two dinosaurs, one patting the head of the other one.
As hardy as the ficus is, unfortunately the fittonia in the back was a lot more temperamental. I thought it maybe couldn't handle the humidity (the guides said you shouldn't let too much condensation build up on the glass) or it needed more light. It unfortunately started getting these strands of mould and eventually became a gloop.
I called the workshop instructor and he said there may be a number of reasons for this, asked for photos to troubleshoot, and he offered to replace it if I came by, but Shoreditch is kind of a trek from here. He said I should take it out so that it doesn't damage the ficus. In the meantime, I also got some grow lights so I can have a bit more control over the environment, rather than be at the mercy of UK winter weather!