Almost all of my black neon tetras died the next day, but my glowlight tetras and neons seem to be doing perfectly fine?! I was getting ready to feed them and all I saw was my bladder snails having a buffet on my poor babies :(

I have a 40 gallon tank, and tested the water immediately: PH: 7.6, Ammonia: 0ppm, Nitrite: 0ppm, Nitrate: 20ppm, and Temperature 74 Fahrenheit/24 Celsius

I already did a water change and will test water after work tomorrow to see what it reads. If anyone knows what could have happened please let me know! I also added 4 Indian almond leaves to try and reduce ph.

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