Your a fishermen (or woman) out at sea, your family has been fishing for generations now it’s your turn to continue that

While out at sea you notice a large tail for a fish before you can get anyone else to notice it’s gone. Then just as your pulling the nets you notice something else. A merperson, your family is excited and they decide to take it back to the mainland

You hesitate as your dad rolls his eyes as he puts you in charge to watch it as he places it in a tank big enough for it