Hello, one of my Lasius niger colonies had mold since the beginning, but now it has spread almost all over the part of the cotton that touches the queen and brood and its like half centimeter deep in some parts. water is still somewhat clean.
I'm thinking moving them elsewhere but the problem is that I do not have any other test tubes.
Any idea what can I do ? and if the mold can harm the ants ?
Yes some mould can harm them. You need to offer them a alternative tube, or piece of pipe, anywhere they can move too. Do not force them to move though, let them move on their own or you will stress the colony. They will move if they feel they have to.