Tetramorium colony

[Camponotus]

They are most likely slowing down because its winter time. They will be fine trust me.

[MadVampy]

Okay, thanks

I realized that probably the formicarium is just too big for them for now, and maybe that's why they won't move in.

I doubt they consider it too big. Yes they have to have favorable conditions to consider it a new home but most of the times a formicarium is always larger when you first move a new colony into one, but they will still use it and grow within it.