3 months into breeding with minimal problems, even sold a few, and lost 3 separate tanks of fry ranging from 2 weeks to 3 months in age in the last week. all are from same male, 3 different females
tank 1: 20 gallon long, ~40 3 month old fry. died over a 3 day period half before and half after a water change. temp 72, heater controller failure or too small. first winter with this tank. nitrates were high, perhaps 80 on the test strip, it was 40 after 50% water change. a different tank with this same spawn is fine. I did drop a mystery snail in right before this happened. I was trying to save him, having problems breathing after I had to medicate a different tank after some fool tried to get away without a quarantine, there were 50% losses in that tank. Snail is still alive. so I at least succeeded there.
tank 2: 10 gallon, 30-6 week old fry all died today, no nitrates, 75 deg, I did water change yesterday and moved some corys in to help with food debris.
tank 3: 10 gallon, 20-2 week old fry all missing a week ago, even noticed a few dead trumpet snails, no nitrates, 75 deg this was a week ago, chalked it up to infant mortality
water is well, softened because of the dissolved iron, 0 GH, 300+ KH, PH 7.6, this is unchanged as far as I know.
I don't test for ammonia, tanks have a lot of plants, so almost always next to 0.
all tanks also have bronze corydoras and mystery snails that are alive
What can wipe out BN that quickly and efficiently? Three other fry tanks and 2 breeders still ok.