Please help, I have a 5 gallon tank with one small apple snail and a black moor. First of all, my black moor is sitting at the bottom of the tank and only comes up when I feed it. I've had a lot of other fish and 3 of them died because of this. My apple snail doesn't look very healthy either. It's always half in it's shell and when I poke it with a net to check if it's still alive it ignores me but a few hours later I see it on the glass .