I just got a chocolate chip starfish for my tank, it’s supposed to be salt water but I got fresh water salt by accident, I put him in and he isn’t moving, his arms a curled up and he’s a bit stiff. The temperature is normal and so I the pH level. I flipped him upside down and he’s not moving i gave him food and he’s not moving. I waited 3 hours and he’s still not moving. Is he dead? What do I do?