Water well leaks water from top black piece on fiberglass tank

Need a bit more here. Is this "tank" an expansion tank for the well system and that metal.

Or is this a water storage tank that's filled with the well pump?

The "black" pipe is this directly off the well pump to tank?

Where this leaks on tank, does it look like an air stem valve like on a car tire?

The tank hooks to the pump on the bottom by the gauge, the tank you could say is a blatter tank that is pressureized. The shrader valve is not leaking. The top black piece never has leaked. The black piece has a cap, and right on top the tank. Inside the house you get hot and cold water while you are in the shower.