Originally Posted by Martian

From the linked site.

That is the most misleading piece of propaganda I have ever seen.

In function, fish nerves are the same as human or chimpanzee or crab or lion nerves. Or the ones in earthworms, for that matter.

Wow, an earthworm must be an intelligent creature with a personality that feels pain, just like us!

Or maybe a dendrite is a dendrite is a dendrite.

A fish brain is little more than a glorified hypothalamus. In fact, a fish brain is the least complex brain in the animal kingdom that can still be classified as such (discounting the neural nets seen in animals like crustaceans). A fish has a large cerebellum and visual cortex in relation to the rest of it's brain and a very small cerebrum (commonly called the 'forebrain'). A fish doesn't even have a cerebral cortex. A fish is not capable of complex thought. The parts of the brain necessary for such are simply not there.

A fish is much closer to a very complicated machine than a thinking creature. It responds to stimuli and uses encoded behaviour to form a complex behavioural pattern. In that sense, a fish does not feel pain the same way we do at all, except how we do in a reflex reaction. You touch a hot stove, your hand moves away. You don't have to think about it, you don't even actually feel pain - your body takes a stimulus and formulates a response, entirely without conscious input on your part. This is how a fish goes about it's daily life.

The human body is designed in such a way so as to require amino acids that are very difficult to acquire from plants. We are herbivores, whether we were designed as such by an intelligent higher power or we simply evolved into it. And frankly, if it's a question of a fish's well-being over that of a human, I'll kill a thousand fish for one man.