It's a widely used proverb with versions of it found all over Europe and Asia, alluding to the idea that organisations fail due to bad leadership. One early ver

It's a widely used proverb with versions of it found all over Europe and Asia, alluding to the idea that organisations fail due to bad leadership. One early version I've found is "a fish rots from the head, not the tail", which avoids the issue you raised, so it's likely it has become abbreviated over time as it became more widely known.