I snagged a picture of one of the blue dragonflies by the koi pond, resting in the reeds.  We lost two of the koi last week - no reason why that I know of.  I tested the water, and the Ph was a little high, but not out of range, but obviously too high for them - that's all I can think it might have been.  The others are doing fine - we are down to 7 koi.