Along these same lines, isn't it better to simply not be exposed to the parasites? I'd rather live somewhere where I'm not exposed to parasites than to live somewhere I am exposed to parasites and just hope my immune system can fight them off.
Are Captive Bred Fish More Susceptible to Diseases?
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Cthulukelele
2500 Club Member
I think most hobbyists who aren't doing vigorous qt of every single thing that ends up in their slice of the ocean vastly underestimate the volume of various parasitic and commensal organisms that end up in/on their fish.
I have a hard time with the concept of fish not being exposed to parasites. It happens. I think the argument of "fish who are wild caught are exposed to lots of things and their immune system recognizes them" is sound.
BUT I also agree that at least ime and the experience of those I know locally captive bred fish have much much better track records when properly acclimated.
The question becomes why? My answer is pretty simple. Big water box is not the natural habitat of these fish. Even the most aquarium suitable fish who are wild caught have been moved into a very alien system vs what they are used to in the wild. Stress. Lots of it.
Captive bred fish know only big water box. It's home. They're comfortable. They're less stressed. Thus they're less likely to present symptomatically from opportunistic infection and be overrun by them.
I could be super far off, but that's how I see it. Get good nutritious food into fish bellies, have lots of biodiversity, feed often, and make sure to address squabbles/make the tank as comfortable as possible. Captive bred fish know the score and the value of their giant food god. Wild caught fish eventually learn too, but it's not the entirety of their experience.
I have a hard time with the concept of fish not being exposed to parasites. It happens. I think the argument of "fish who are wild caught are exposed to lots of things and their immune system recognizes them" is sound.
BUT I also agree that at least ime and the experience of those I know locally captive bred fish have much much better track records when properly acclimated.
The question becomes why? My answer is pretty simple. Big water box is not the natural habitat of these fish. Even the most aquarium suitable fish who are wild caught have been moved into a very alien system vs what they are used to in the wild. Stress. Lots of it.
Captive bred fish know only big water box. It's home. They're comfortable. They're less stressed. Thus they're less likely to present symptomatically from opportunistic infection and be overrun by them.
I could be super far off, but that's how I see it. Get good nutritious food into fish bellies, have lots of biodiversity, feed often, and make sure to address squabbles/make the tank as comfortable as possible. Captive bred fish know the score and the value of their giant food god. Wild caught fish eventually learn too, but it's not the entirety of their experience.
Lionfish hunter
Valuable Member
I am yet to find a fish that is able to fight off ich and velvet, which probably kills more fish than all other parasites and disease combined in aquariums. If they are exposed they get it. Once they get it, they have it forever unless it is erraticated with treatment and the tank goes fishless for a long time. What is this advantage a wild caught fish will have over captive bred? They will both get it if exposed. They will both have it forever if not treated correctly. They will both be completely overwhelmed if they get it and are stressed or picked on. There is just a lesser chance of the captive bred being as stressed. Grew up in a aquarium, not shipped around the world, fatter because it has gone less time not eating and more likely to aquarium food. This thought that wild caught fish have immunity to ich and are less likely to become infected is completely wrong, and any immunity they have built up proves useless when stressed in a tiny glass box. There is no advantage in this scenario for wild caught.
Cthulukelele
2500 Club Member
Your comment about ich is interesting to me. I've never lost a fish to ich, but I 100% have it in my display. About 50% of my new additions will get a spot or 2 when I add them, but they always recover in a day or 2. If they are getting bullied they might get a spot or 2. Is this not a common thing to see? I thought a lot of the big show tanks that exist knowingly have ich and practice ich management. Are you talking about once it progresses to "fish is covered in ich?"
Lionfish hunter
Valuable Member
And because cb fish are not exposed to these parasites, they do not bring them into your system. Assuming you either source them from the breeder or buy them from a fish store that has captive bred only tanks which many do.
Lionfish hunter
Valuable Member
There are other things that can cause a white spot or 2 on a fish. My moorish idol has a virus that looks exactly like ich, just 1 or 2 white spots. Many people say they have ich but how is this confirmed? Put any stressed fish in a tank with nothing being done to stop ich and it will be covered. I’ve done it more times than I can count over the past 20 years. the same thing happens no matter what, I have watched so many fish die. What are you doing to manage ich? Because a new stressed fish being bullied that has ich will fill that aquarium with thousands of parasites. Something would have to be done to limit the quantity of parasites in that aquarium to keep said stressed bullied new fish from being reinfected.
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Lionfish hunter
Valuable Member
One thing maybe this discussion is missing. Captive bred fish are shipped as tiny infants. Being so young, small, and underdeveloved. They are fragile. I can’t imagine they would do well if they were to be dropped in a tank full of parasites. Not because they do not have immunity, but because these guys are little frail babies. Maybe we are discussing the wrong thing here. I bought 5 biota yellow tangs a couple years ago and 2 were killed from injuries given to them from being in a smallish tank with a young queen angel. Fast forward to today and they are full grown and strong. But everybody should be aware that when they order cb fish, they will come as tiny nickel sized babies. They cannot defend themselves against much bullying and I can’t imagine any infant fish does well with parasites.
MnFish1
10K Club member
I know. I was just making the point that fish immunity (and human immunity) - applies to parasites as well. BTW - there have been at least a couple studies - mainly in Vietnam - that at times (its more seasonal) 40-50+ percent of fish have active infection - and there are also instances of large die-offs from Cryptocaryon in the wild.
MnFish1
10K Club member
Another interesting thing is that as hatchlings, 'baby' fish have some immunity from their mother. Plus they have the innate immunity that would be no different between a captive and wild specimen. However, in general, I agree with you that CB fish being exposed to an Ich management tank is going to cause mortality. Probably not 100% - but more than acceptable.
Cthulukelele
2500 Club Member
I have a few fish with lympho. I imagine this is what you're referring to. It could just be lympho I guess, but I will occasionally get a fish with 4-6 dots which is uncharacteristic of lympho. My fish usually only take a day or 2 to settle in and get fed 4-6x daily. Usually, there are 0 active spots in the tank. I imagine it could get to plague proportions, but I haven't seen it yet. I could also just be ignorant. That's entirely possible. Fish disease is by no means my specialty
MnFish1
10K Club member
Of course. But - whether we like it or not - humans (which is what we were discussing) are exposed to potential parasites every day. The point is/was there is immunity to various parasites in both fish and humans
Cthulukelele
2500 Club Member
What I see is pretty comparable to what I've read about the experiences of @Paul B with fish illness.
MnFish1
10K Club member
I think you're correct. The reason Ich can grow to huge numbers in tanks is probably much more likely in tanks with fish that have not been exposed to CI - OR - those partly treated for CI (i.e. in chronic low-dose copper) at an LFS, and stocking density. Stocking density in a tank has a huge impact IMHO - on the potential for CI to grow to exponential proportions
Cthulukelele
2500 Club Member
That makes sense. I'd also imagine fish choice would be a big deal. I know acanthurus tangs and blue tangs can become essentially ich factories. I probably wouldn't attempt one in my tank because of it.
MnFish1
10K Club member
FYI - here is an interesting article on wild fish. https://iopscience.iop.org/article/10.1088/1755-1315/137/1/012094/pdf
Cthulukelele
2500 Club Member
I actually have been surfing the older posts out of boredom and fish fever the last few weeks and stumbled upon that article. It's a super interesting read, and it's really eye-opening to the prevalence of these sorts of things in the wild.
Very few people keep a tank like Paul B's. They keep a raceway, high density stock of fish, usually Tangs in a SPS tank, maybe dry rock start at one point. He has a reverse gravel filter and ozone. I couldn't even find a gravel filter to fit my tank when I tried.
Cthulukelele
2500 Club Member
100% agree there. I don't think I do keep a tank anywhere near his. I just had read his description of what he sees with disease and how it compares to what I've seen in the past.
MnFish1
10K Club member
The total surface area of the fish is also important. For example a pipefish 3 wrasses and a Blenny in a 200 gallon tank is much smaller than 6 tangs in the same size tank - and the surface area of the fish would seem to me to directly relate to the rapidity of multiplication
Cthulukelele
2500 Club Member
That makes sense especially when you hear about the fish that have the most problems. They're always the ovular ones with the thinnest slime coats. I know the fish that most often presents with a couple spots are my tomini tang and my male clownfish--for very different reasons. The clown is always a little stressed by his not-so-loving wife constantly reminding him he's a boy lol
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