Platys, mollys, etc. are bad stock from chain stores. Overbred and overstressed.
I've seen fish get drug under the substrate by trumpet snails in a matter of minutes, if that helps. Dead cardinals would be an easy treat for them.
Best of luck finding the tank and you did a very smart thing, you asked. People on the forum have a ton of knowledge and can save you time, money and
Thank you! For now I only have two stones, but I want to take another several stones. I pay attention to increasing hardness, because these rocks increase