we have had a conch in our salt water tank for about a year. The last few days, he has climbed up to the top and is sticking his tenacle(?) out of the water. Salt level is right, and he has climbed up the side before, but never just stayed at the top like this. He usually moves around on the bottom and will aometimes stay in one spot for a few days. Does he need something? Is he sick, or just exploring?