I have a freshwater aquarium with guppies, molly, pleco, algae eater, otto cat, figure 8 puffer, angel fish, shrimp and neon tetras. My two snails died, but all of the fish are doing great and the tank is cycled. I do keep a small amount (smaller than 1 tbsp/5 gallons) of pure salt in the tank. I had a small brown algae diatoms outbreak at the end of the cycling of the tank.
What killed these so called “hardy” snails? What are the requirements for snails to thrive in an aquarium?