To add to this, the jag pair had a big bust up, so I had to divide them. I'm wondering if it has anything to do with the temperature in their tank being higher than they're used to.
On the positive side, I have over 10 baby guppies from the red-tailed females I bought (from Ely Aquatics) a couple of weeks ago. The females don;t appear to be eating their offspring, so hopefully the babies will turn out to be 'pure strain' and I can establish a pure breeding colony.
Even better news is that the pair of super red kribs I picked up at the CDAS meeting have just brought out their first spawn (hence the recovering Bettas!).

Things are ticking over nicely in the fish room. My biggest challenge at the moment is working out how to overcome the problem that many of the tanks have suspended matter in the water as a result of having no substrate. Makes for some pretty nasty photos.