Mollies dying for no reason?
So I've had a weird predicament lately -- I had a school of about 12 black adolescent mollies, all of them born from an old pair i used to have but rehomed, and for the past week or two they've started dying two and three at a time. I have four or five left, one male, the rest female. But it's weird because it's only affecting my mollies and not my school of tetra or corydoras or my betta.
My tank is a 40 gallon long, planted, cycled. Two sponge filters with 40g tetra whispers. Two airstones. I dose the tank every week with Prime, Flourish, and CO2 Booster. I did use a few doses of Algaefix for an influx a couple of weeks ago, but the algae is gone now. I do weekly water changes with a nifty python system, usually did about 25% but upped to 50% starting with the deaths. I have one betta, four emerald corydoras, 7 black neon tetras, an assassin snail, and now 4-5 black mollies (they're mutts, they look like sailfin but their parents weren't nearly as big).
Tonight's test had me at 0ppm ammonia, nitrates, and nitrates, and around 7.0 ph. I checked my temp and it WAS a little high at 85 degrees. My amazon swords take up about 75% of the tank, so it's well planted. I'm just not sure what's going on!
Prism ♂ | Sunny ♀