This fish riddle is a wording test rather than a difficult calculation. You begin with 10 fish and are told that all but two die. The phrase “all but two” means that eight die and two remain alive.
But the question asks how many fish are left, not how many are still alive.
Answer: 10 fish are left.
The eight dead fish do not suddenly disappear from the tank, so all ten fish are still physically there. Only two of them are alive. If the question had asked how many survived, the answer would be two. That small wording difference is what makes this classic riddle tricky.
