No more deaths since the last of the pearlscale Angels yet, making her hold feeding until either the second or the third day.
It was definately the filter that had given up, the motor wasn't going.
The tank is 100L and the Fluval internal filter said it cycled about 900L an hour, so we assumed it was suitable.
She's lost in total 6 small Angels, 3 Siamese fighters and a couple of Glowlights. But she's not giving up which is good