Who owns the fish?

Here's a riddle I found here, supposedly attributed to Albert Einstein. There is a solution, if you can't figure it out, ask me!

There are 5 houses in a row, and in five different colors. In each house lives a person from a different country. Each person drinks a certain drink, plays a certain game, and keeps a certain pet. No two people drink the same drink, play the same game or have the same pet.

The British lives in a red house.
The Swedish keeps dogs.
The Danish drinks tea.
The green house is on the left of the white house.
The green house owner drinks coffee.
The person who plays tennis rears birds.
The owner of the yellow house plays chess.
The man living in the house right in the center drinks milk.
The Norwegian lives in the first house.
The man who plays poker lives next to the man who keeps cats.
The man who keeps horses lives next to the man who plays chess.
The man who plays billiards drinks lemonade.
The German plays golf.
The Norwegian lives next to the blue house.
The man who plays poker has a neighbor who drinks orange juice.

Now, who owns the fish?