So over the course of 48 hours I lost all but 3 of 80 fry. The remaining 3 are about to be culled to be put out of their misery.

I have taken images of the obvious illness, yet note that I have only noticed these white spots developing today on these fish. The previous ones that died did not display any clear sign of infection or illness.

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My water is changed daily ranging from 50 to 80%.
pH - 7.5
Temp 29
PPM 50 (remineralized RO)

Amm - 0
N02 - 0
N03 - 0 (undetectable on SERA/API kits)


Is this ich, or velvet? Furthermore, could this be the culprit behind the sudden onslaught of all of the fry without any clear symptoms, or is this likely a secondary infection caused by stress of something else that wiped them out?

Recently taken BBS, in multiple, very small amounts.

Any advice would be most appreciated.