At 25 mm long this is our smallest local damselfly. While this species doesn't seem to be as common as the Eastern Forktail it's well worth seeing, the males look like little jewels as they flit through the foliage.
Its smaller size, the "exclamation mark" shoulder stripe, and lack of blue on the end of the abdomen distinguish the male Fragile Forktail from the Eastern Forktail.
Not sure what kind of behaviour this is ... perhaps the damselfly equivalent of obelisking?