I'm jealous. Still waiting for my provider's shipment to arrive on island. Definitely a very good looking group you've got there. Keep the water pristine and you shouldn't lose any.
It's funny when I think about it, but since I purchased my Lamotte Spin Touch photometer and am able to see more precise nitrate readings I haven't lost a fish. My goal was to keep nitrates below 10 ppm but in reality my readings haven't gone past 6 ppm before I do a water change. It was hard to accurately know what my nitrate readings actually were for all the years when I used the API master kit test. Losing a fish every so often was more common then.