I think there are species that are in the Animal Kingdom that the ethics of veganism don’t apply to. Corals for example are - just as plants - better described as robots but as feeling animals.

The discussion where this robot behaviour ends and emotional life begins is very hard (fish have feelings imo). I avoid this gray area by how unhealthy eating marine, filtering animals has become (for example due to mercury).

Oh, and also the awful practices of maritime fishing that endanger the biggest and most robust ecosystem on earth.

Fish do certainly feel pain but there’s an important distinction to be made between pain and suffering and I think your friend is confusing the two. Suffering is harder to define but it could be defined as the ability to understand pain - if an animal can become depressed, can remember it’s pain, can develop phobias, can grieve. It’s less clear to what extent different fish can suffer. Despite how callous their reasoning may sound to an experienced vegan they actually sound like they’re engaging morally with the issue and it’s a great starting point for further reflection. I would encourage them to go pescetarian to start with and then gently introduce them to fish welfare and harmful fishing practices when they are more comfortable with a meat free diet.

“I mean, it’s possible that they don’t,” no it isn’t.

The easiest way for humans to feel superior, is to claim that other animals are inferior. Some people even choose to believe that humans are not animals.

Humanity is a species that is happy to have human slaves, as long as it is legal and socially acceptable to do so. They have even fewer qualms treating other species as objects.

I have not watched Dominion, but I am curious as to how they arrived at the conclusion that fish do not feel pain.

1. Ask them to clarify and give relevant sources for the claim.
2. Ask them what extent they are willing to extend their argument. Clearly, they make a distinction between humans and animals. That’s fine, but then, is it moral to kill and consume a sufficiently mentally impaired human?
3. If we have reasons to believe that the being can feel pain, albeit with a lack of certainty, wouldn’t it be morally superior stance to not kill and consume it?

Chances are, they are in cognitive dissonance, and they do not want to think/act about all this. So, despite knowing the philosophical arguments around it, they can rationalise by just saying “but it tastes good”, and “lol, they are not human”. I, personally, have found no way to talk to such people. So, if your friend is anything like that, good luck, fellow vegan!

They also state that they have watched dominion and nothing clicked.