How do you know if your sea monkeys are dead?

Sea snails have dark brown or black trapdoors that they use...when they're moving, the door is on their back, but when they're inside, and you look inside, there's the door covering them.

If it has the door, it's probably alive, but if the snail is just hanging there without the door, then it's most likely dead.

You can take it out, and see.

If the snail is upside down too, and there's no door, then they're probably dead too.

Sometimes the snails like to move around at night, because other fish in the tank bother them. So they close themselves in the daytime.

My snails are bothered by my frogs, because they're bitten, so they usually eat at night.