One of my two otos became depressed after the other one died (by jumping out of the tank). I've seen fish hide in fear, look stressed with clamped fins, and practically wag their tails with enthusiasm when I approach the tank with food. It would never cross my mind to think that they didn't have emotions. Thanks for posting the BBC article.
Well....*ahem*... I believe in God. it used to be that I stated my religion was "infinity" because it is that key element that a finite creature such as ourselves can never understand. Now I attribute that to God and state simply that just because I can't understand it doesn't mean it is not real.look up how much DNA is contained in human cell (for example) and you will see that a lot of intelligence can be packed into something so small you cannot see it with the naked eye.
So how can we say with any certainty that a fish runs only on instincts? How do we know that a creature must operate exactly as a human in order to have human like traits?
I would be Leary of anybody who states matter of factly that they already know the answer to this mystery.
But that's just my two cents for what it's worth....