I don’t know what the plant is, but the green stuff on the branches is algae and not a problem.
How long have you had it? Did you plant it in that pot or was that the pot it was growing in? How often we’re you watering it? Did you feed it?
Normally I wouldn’t recommend feeding a struggling plant but if you use something at 1/2 strength it might help. A water-soluble fertilizer will have a faster response. Just don’t think that “if a little’s good more would be better”, that would undo the gentle nudge it needs.