David Mitchell and Sandi Toksvig in “Unfinished Business”

David Mitchell

Why isn't there actually a fish that lives in trees or on the land, cause, there's, you know, there are penguins which live in the sea and mammals that live in the sea. Why hasn't a fish had the gumption to start living like a rabbit?

Sandi Toksvig

I think it's lack of ambition.

David Mitchell

Bats! Bats are mammals, they can fly...it just doesn't make sense. The fish aren't trying.

Sandi Toksvig

No. I think what you need to do is to start diving and give those fish a good talking to.

David Mitchell

I wouldn't need to dive if there were fish running on [drowned out by laughter]

Sandi Toksvig

The mangrove killifish lives on land.

David Mitchell

Well done!