Got 6 zebra danios, and one has died after 4 days. I thought they were hardy?
My water has been very good, always:
pH 7.6 - 7.8
Ammonia: 0
Nitrite: 0
Nitrate: <= 10ppm
I think the one that died seemed to be quite pale the night before, and his spine looked like it was curving downwards... his body wasn't straight, and he looked a bit awkward. I found one of my gouramis nipping at his body, which had been half eaten by the morning. He was almost all white, with no stripes really - is that what happens after they die?