Einstein's Intelligence Quiz

I stumbled upon this quiz here supposedly set by Einstein and that he had mentioned that 98% of the people in world would probably not be able to solve it. I tried it the first round, by trying to draw diagrams around it, but it felt not right, so I tried another method which first took me an hour first time, but eventually I still managed to solved it.

Subsequent tries by me using the same method without referring to my previous work, I could solve it within 10-15 minutes.

EINSTEIN's QUIZ

There are 5 houses in 5 different colors
In each house lives a person with a different nationality
These 5 owners drink a certain type of beverage, smoke a certain brand of cigar, and keep a certain pet
No owners have the same pet, smoke the same brand of cigar or drink the same drink.
Here's the question: Who owns the fish?

1. The Brit lives in a red house
2. The Swede keeps dogs as pets
3. The Dane drinks tea
4. The green house is on the left of the white house
5. The green house owner drinks coffee
6. The person who smokes Pall Mall rears birds
7. The owner of the yellow house smokes Dunhill
8. The man living in the house right in the middle drinks milk
9. The Norwegian lives in the first house
10. The man who smokes Blend lives next door to the one who keeps cats.
11. The man who keeps horses lives next door to the man who smokes Dunhill
12. The owner who smokes Blue Master drinks beer
13. The German smokes Prince
14. The Norwegian lives next to the blue house
15. The man who smokes Blend has a neighbor who drinks water

With these 15 clues the problem is solvable.
Here's the question: Who owns the fish?

The solution is posted in here... but try to do it yourself before going there. I was surprised that I had used the same matrix that Mr Tan used, but I had done it on paper rather than in Excel as recommended by him.