Answer:
I am the kind of fish that chases a mouse.
Two bodies have I, though both joined in one. The more I stand still the faster I run. What am I?
Who is the most foreign visitor you could imagine?
I am a nut with a hole. What am I?
When you stop and look you can always see me. If you try to touch you cannot feel me. I cannot move but as you near me I will move away from you.
Give it food and it will live, give it water and it will die.