What does malolactic fermentation look like?

Last week I racked off my first two batches into glass carboys. Due to some kind of discrepancy in my Cyser, I had to add back about two pints of juice in order to raise the level in the carboy, so it had abubbling ferment going for about the past week.

But my Perry had fermented out to dryness and has just been sitting there in the carboy. It is starting to get a little scum on the top, but no bubbling in the airlock. Is that normal? If not, what can I do to fix this?