These 4 little fellers spend like 90% of their lighted time staying right against this side of the tank. Anyone knows if this is a potential issue?

They've been joining the tank for more than 3 months by now. I don't think they are stressed but perhapse if I buy more of them they will be more willing to swim around different parts of the tank more?

They've been joining the tank for more than 3 months by now. I don't think they are stressed but perhapse if I buy more of them they will be more willing to swim around different parts of the tank more?