do fish feel pain?

[redbucket]

Before I started my aquarium I was a sport fisherman -- many people I knew who enjoyed the same hobby believed that fish were incapable of feeling pain. Since I have started keeping small fish in a big glass box, I have come to believe that fish are aware of pain, whether it be physical injury (hook in the mouth, another fish nipping at them) or poisening (have noticed strange behavior when nitrites or ammonia are high).

What do you think? Do your fish feel pain? I was reminded of this topic when I read a study had concluded that invertabrates are incapable of feeling pain. Has anyone heard of a study of fish and pain?

[carpguy]

There was a long and heated thread on this ways back. Started with a study that said, more or less, that fish couldn't feel pain because they couldn't be conciously aware of it. This seemed kind of silly to me. The author of the study also skipped evidence or experimentation or most of the sort of things you'd expect in a study.

I found a few studies that suggested that some (but not all) fish "pain guard", avoid using injured areas. Other fish don't, seem oblivious to injuries. Kind of hard to tell.

In general, I think assuming they do is better practice than assuming they don't, just going by harm done if I'm wrong.

[biogirl361]

I always try to treat my fish the same way as I'd treat a cat or dog, which is to say, the same way I'd want to be treated if I was them... I guess to me not even a little fishie life is too small to take good care of. If I took them under my care then I am responsible for them and have to do my best to honor that.

in other words.. i just assume they feel pain and other emotions b/c like someone else said i rather treat them well and not have them know it than treat them ill and have them in pain.

[Tuolumne]

I would guess and say yes because:

Pain is what helps living creatures realize they've been injured, avoid injuring it further and causes us to guard an injured part until it heals.

They may not experience it in the same way that we do, and certainly with less self-pity...but I would say that they do experience pain/discomfort in some way.

Anyway, that's just my guess. Here are a couple of links to articles that make you think, though...

http://www.smh.com.au/articles/2003/02/10/1044725683181.html?oneclick=true

http://news.bbc.co.uk/2/hi/health/4195437.stm

[reiverix]

I'm not sure fish feel pain the same way that we do. But I think they must know when something is not pleasant, like ich or fungus.

[happychem]

Knowing pain and knowing injury are two very different things. I don't believe that fish feel pain, but I don't think that that's licence to treat them badly. They still suffer under poor conditions.

Pain isn't an advantage in a life or death situation, this is why we have various mechanisms that shut off pain. As soon as fight or flight kicks in our pain receptors are dulled/shut off. Why? because if you're running from something that wants to eat you, it's better to make a broken ankle worse than to get eaten because you're trying to hop.

I think that categorizing fish into the broad category or 'fish' is probably too limited, also. There are probably some fish that do feel pain and some that do not. Reacting to a negative stimulus is not evidence of pain receptors though, just means that the subject in question is alive and wants to remain that way.

In the end, I don't think that it matters. Whether or not your aquatic inhabitants can feel pain, you have, by choosing to keep them, accepted the responsibility to care for them to the best of your means. This is the mantra of ownership, no matter what animal you own, you are responsible to provide it with as good a life as possible and if you are unable to provide it with minimum acceptable living conditions, then you should not be owning said animal.

**I'm using the non-specific "you" in the above paragraph, btw. No one should take that as directed at them perspnally. Unless you're a bad owner ;) **

[mogurnda]

There is a difference between nociception (detection of a noxious stimulus) and pain, which is the subjective experience. Whether fish feel pain is a matter for philosophers. As a neurobiologist, I can say that there is evidence for nociception, but that debate continues in scientific circles.

Seems to me that if leeches and insects have neural pathways to process painful stimuli (which they do), I'd be surprised if fish didn't. It is pretty advantageous to know that something is harming you and that you should go elsewhere.

[aquariumfishguy]

This is a topic beated to death. Anyone have the link to the not so old thread? We all pretty much stuck to what we believed. However, one shouldn't confuse pain with injury as already pointed out. I am on the scientific side of the fence here, which is that they do not indeed 'feel pain'. Pain is just not physical, but then again... all of this is covered in the other post. ;)

I will supply the link to the reputable site though: http://www.cotrout.org/do_fish_feel_pain.htm

[happychem]

Like I said, it's really irrelevant whether they do or do not. Even if they cannot, it's not licence for us to mistreat them.

[MikeO]

I am going to guess yes. why would a fish that has ick try to scratch it off if it did not feel some sort of discomfort.

[oztun]

I agree with the last two post... Mike beat me to it. They scratch on rocks so they can itch and itching to me is a form of pain. In my mind that proves fish can feel pain. I'm using the definition that pain is discomfort.

And also the post before that... It doesn't matter if fish can feel pain. As the most advanced creatures on earth I feel it is our duty to be humane by assuming animals feel pain and treating them accordingly. Otherwise if a person is inhumane then the rest of us have no reason to be humane to that person. Come mess with one of my dogs or cats and I'll show you what I mean.

[mogurnda]

Just one last picky comment. Pain is not discomfort, at least not to people who study it. In mammals, noxious stimuli are detected by a completely different set of receptors than are things like itch or uncomfortable pressure. Same is true for flies (I can give a long, boring explanation if needed). Real pain is a sensation that is designed to be difficult to ignore.

I agree, though, that it's irrelevant whether fish can suffer pain when you are in charge of taking care of them. The goal should be to provide them with a comfortable environment. Otherwise, why are you doing it?

Also, I just re-read the original post. First, whatever you read about invertebrates being unable to sense painful stimuli is not true. For example, as I mentioned in a post above, it has been known for decades that leeches have specific neurons, called "N-cells" that respond to noxious stimuli.

Redbucket also asked for references, so here's the abstract of a review on pain in lower verts, mostly fish:

Brain Res Brain Res Rev. 2004 Oct;46(2):123-30. Related Articles, Links

Evolution of nociception in vertebrates: comparative analysis of lower vertebrates.

Sneddon LU.

School of Biological Sciences, University of Liverpool, The BioScience Building, Liverpool, Merseyside L69 7ZB, UK. lsneddon@liv.ac.uk

Nociception is an important sensory system of major fundamental and clinical relevance. The nociceptive system of higher vertebrates is well studied with a wealth of information about nociceptor properties, involvement of the central nervous system and the in vivo responses to a noxious experience are already characterised. However, relatively little is known about nociception in lower vertebrates and this review brings together a variety of studies to understand how this information can inform the evolution of nociception in vertebrates. It has been demonstrated that teleost fish possess nociceptors innervated by the trigeminal nerve and that these are physiologically similar to those found in higher vertebrates. Opioid receptors and endogenous opioids are found in the brain and spinal cord of the fishes and morphine blocks avoidance learning using electric shock as well as reducing nociceptive behavioural and physiological responses to noxious stimulation. Comparative analysis of the fishes and higher vertebrates show that fish possess less C fibres than higher vertebrates. The electrophysiological properties of fish nociceptors are almost identical to those found in higher vertebrates suggesting the evolution of these properties occurred before the emergence of the fish groups.

[StreetCypher]

You mean this thread AFG?

http://www.aquariacentral.com/forums/showthread.php?t=37810&page=1&pp=15&highlight=fish+feel+pain

[SnakeIce]

Fish have nerves and a densely packed area of nerves known as a brain.

they detect light waves(eye), current/pressure changes(lateral line) and to some degree can sense contact with other objects. Without them haveing language as we know it the discussion about how they interpret the signals their nerves send their brains can't be more than a philisophical one.

you might deside that anthropomorphism or assigning human emotion to animals is to much of a stretch to do, but that doesn't change the fact that electrical impulses travel along thier nerves just the same as the ones that trigger the muscles in my hands to type this.

at one time we tried to say that useing tools was a uniquely human atribute, but there are many examples that refute that idea. like wise language was thought to be solely human, but Koko the gorilla, dolfins and other animals have shown to understand and use sound or gestures to comunicate.

I won't say that fish have emotion, but they do sense things... its up to us to decide if we want to try to put it in words or not.

[Paccula]

In general, I think assuming they do is better practice than assuming they don't, just going by harm done if I'm wrong.

I agree whole-heartedly. not just for fish, but any living creature, it is always better to treat them with respect than to abuse them. personaly, I think fish do feel pain