A slice? Dude, mines made of applesauce and whole bananas and it never stinks no matter how old it is. I totally admit I've had some sitting for like 4 months. I'm used to these things blooming like 2-3 months out so I ass drag about tossing them. You can put a dish of some sort (people like using yogurt tops) in the tank with a slice of banana in it and then the frogs have a feeding station of sorts. I hear that works really well.