Is a "quarantine tank" really that essential?

[mcarroll]

I agree with @Husker that there seem to be more parallels than not with fish immune systems and our own.

On average the guidance here has mostly to do with treatment options. Diagnosis get second shrift. "Background things" like stressors and immune systems do not usually enter conversation.

So any and all additions to the conversation are welcome. Especially somebody with related experience!!!

 

[Areseebee]

Why do you get a flu shot yearly

This explicitly is not why we get a flu shot every year. The flu virus mutates very quickly (as most viruses do) and each years specific strain does not get recognized by the same antibodies year over year. Immunological memory is hugely variable for reasons I don't understand (I.e. tetnus every 6, chicken pox once in a lifetime). I'm not really on board with a lot of the tie ins here with immunology, atleast beyond the simple "better health is better function" in general.

That being said, I am fully on board with the nutrition aspects of what you are saying. We are really only beginning to appreciate how important the microfauna in our body (and organisms in general) are for shaping our fitness, how we respond to drugs and our succeptibilty to pathogens (literally this is what the three labs next to mine explicitly study). To me the best answer is to limit source exposure to the worst pathogens through good qt practices and keep them healthy with a good natural balance of microfauna through most of the feeding regiment you discuss.

Finally, why do people keep referring to quarantines as "sterile" and to qt'd fish as "germ free" neither is true in any sense of the word and at best I think they are unintentionally misleading (for instance in the hospital comparisons).

 

[Areseebee]

I agree with @Husker that there seem to be more parallels than not with fish immune systems and our own.

On average the guidance here has mostly to do with treatment options. Diagnosis get second shrift. "Background things" like stressors and immune systems do not usually enter conversation.

So any and all additions to the conversation are welcome. Especially somebody with related experience!!!

There's a well known evolutionary split with jawed vertebrates, everything on our side of that split has a similar innate + adaptive immune system. It's actually the reason people study lampreys and other jawless fish.

 

[mcarroll]

There's a well known evolutionary split with jawed vertebrates, everything on our side of that split has a similar innate + adaptive immune system. It's actually the reason people study lampreys and other jawless fish.

You've piqued my interest as I haven't bumped into authors mentioning that split yet! Any starting points I could look up for reading that you'd recommend would be welcome!! (Or even if you can elaborate some!!)

I wonder if that split 100% applies to our learning – it'll be interesting to see. There have certainly been a long list of similarities – not just with mammals – that most authors I've bumped into so far seem to cite. When it comes to polypeptides, for example, it seems we're very similar in our immune capabilities.

I think that it could be accurate to say that our immune toolboxes are "very similar". Or at least "meaningfully similar".

 

[Areseebee]

It's a really amazing split in evolution. Here's what Janeway (a popular immunobiology textbook... in fact it's called "Immunobiology" so you know it's definitive!) has to say about it in his introduction:

"It has been known for at least 50 years that all jawed fish can mount an adaptive immune response. On the other
hand, hagfish and lampreys, which are jawless vertebrates, lack all signs of an adaptive immune system: they do not
have organized lymphoid tissue, they lack primary immune responses, and most importantly, they do not exhibit
immunological memory. By contrast, even cartilaginous fish, the earliest jawed fish to survive to the present day,
have organized lymphoid tissue, albeit primitive, T-cell receptors and immunoglobulins, and the ability to mount
adaptive immune responses. What makes the two phylogenetically related groups so different? And why are they so
different? That is the mystery of the evolution of adaptive immunity, and what a mystery it is!"

He goes on obviously. Interestingly, I think we know now that this isn't true, jawless also have an adaptive system but it's different in terms of how it generates antibody diversity (my copy of Janeway is probably a few versions old at this point!). I bet there's good non-text book examples too but Janeway is the closest I've ever come to exposing myself to immunology, it's an incredible topic and I'm sure I'm really exposing my ignorance at this point!

 

[Husker]

Janeway was a great scientist, and that is a great textbook. I have used it in the past.

"Adaptive immunity" means antigenic specificity. Meaning, jawed fishes have the capacity to sustain specific immunologic memory against antigens such as those causing particular ailments in the aquarium. This should keep these infections at bay, through T cell and antibody-mediated mechanisms. However, this is more complicated when it comes to chronic or persistent infections with varying levels of antigen presence.

 

[mcarroll]

"It has been known for at least 50 years that all jawed fish can mount an adaptive immune response. On the other
hand, hagfish and lampreys, which are jawless vertebrates, lack all signs of an adaptive immune system: they do not

That division I am aware of.

And for the purposes of studying immunology I can definitely see why that comparison would be interesting. I think for our purposes both the adaptive and innate immune systems are extremely important. The innate system is also foundational so perhaps deserving of more interest from us than other aspects.

 

[nervousmonkey]

I agree with @Husker that there seem to be more parallels than not with fish immune systems and our own.

On average the guidance here has mostly to do with treatment options. Diagnosis get second shrift. "Background things" like stressors and immune systems do not usually enter conversation.

So any and all additions to the conversation are welcome. Especially somebody with related experience!!!

This is put so well Mac. This is the reason why I brought up the idea of a small write-up on immunology, which is not something we talk about, because our reefing community doesn't have anyone (that I am aware of) that can speak on that level. It is quite true that our guidance is treatment options, and that is wonderful, but what about the other side, or more specifically a side we have not heard before now? What are the stressors on a fish that cause an immune reaction that is a suppressant? Man I would LOVE to know that stuff, and I bet that even though you (@Husker ) may have very theoretically and scientifically driven logic behind your arguments one way or another, it is what we as reefers want to hear.

I would love to read a paper from you Husker. It is something I have yet to learn, and I am not sure if we as a community will get the chance to hear from someone who can speak about fish immunology!

Anyway, if anyone else wants to learn about fish health and how our friends in our glass boxes react when stressors and disease come their way, please come throw your vote into the ring to signify support so we can read what Husker can teach us.

Cheers!!!!

Lloyd

 

[Paul B]

That's not how nosocomial infections are spread through a hospital. It's not because the place is too clean, but because something was dirty. It's from people that don't wash their hands and/or equipment or isolate properly or in a timely manner.

Lionfish, I did not come up with that. That was "Popular Science Magazine" (I added a few lines to it)

Quote: (kind of)
"Popular Science" (August 2015) there is an article about this very topic. The author states that the most germ free environment today is on the International Space Station. Everything is sterilized including the air. All the surfaces are coated with bacteria limiting coatings, even the water is treated with iodine and biocidal nano silver so the only bacteria present are the ones coming from the astronauts themselves. They can't open a window or send out for Pizza (I added that last sentence) so there is no fresh influx of microbes to balance the ecosystem. Sounds like quarantining doesn't it? ( I also added that sentence) He also states that a loss of gut bacteria correlates with many diseases and could impede longer space travel. If we lose our gut bacteria, our immune system goes dormant.
In the real world bacteria, viruses and parasites evolved right along with other organisms that help keep each organism in check. They have their enemies and friends. When we mess with the system by using antibiotics or extended periods of quarantine, or remove living bacteria from their food, we are dooming the fish to a life where they are on the verge of getting a fatal disease.
This is also the reason so many diseases are contracted in hospitals, a place where great pains are taken to keep the place clean. They are clean, so the only bacteria present are from sick people with no other bacteria or viruses to counteract them. It is now thought that people using those hand sanitizers from very young are at a higher risk of becoming an allergic toddler.
End.

Bob, I realize we don't quarantine in a germ free environment as that would be impossible, but we try to quarantine in a parasite free environment and I think that is a mistake. Unlike most people I want parasites living in my tank, yes, including velvet.
Why is it that my fish are immune? Why can I add fish any time with any disease and have no problems? I can't see the parasites or know their friends but I "think" they are happily living in my tank and have been for decades.
I always mention feeding my fish with live foods as much as possible, that is to provide living bacteria to the gut of the fish. I learned that through trial and error but lately there has been research (which I linked many times) that proves fish require living bacteria and parasites in their diet to remain healthy and immune. I wish I came up with that myself, but I didn't.
People have said our immune systems are much like fish. They are not. The only similarity to fish is that we both have mechanisms to kill certain bacteria, viruses and parasites. We humans are also covered in parasites, on our skin and in our guts.
The main defense a fish has from diseases is in their slime. Most of us don't exude slime. Well I did date a slimy girl once but I digress.

Here is something I published but I am not smart enough or good looking enough to have come up with it myself. I did a lot of research to find out all of this but my experience confirmed it for "me".
This is where we differ from fish as we don't regenerate limbs or exude slime. We also don't make our antibodies in our kidney as fish do and fish have no bone marrow as we do which is where we make most of our antibodies. Fish have anti-parisitic properties on their skin, we have tattoos, "Right Guard" and little else.
It takes much more calories in a fish to stay immune than us. That is because (as I said) fish are in water and disease organisms, especially parasites can swim better than they can fly and fish constantly eat parasites and harmful bacteria at every meal. We tend to cook our food and try not to eat rotten, live food or "each other" as much as we can. It is also because fish exude slime which washes off constantly. Have you ever tried to hold a moray eel? You can't. And if you did, you would be covered in slime as those things are full of the stuff. Pick up a hagfish, then kiss your girlfriend.

The many roles of fish slime
The first way slime protects the fish is mechanical. Slime traps bacteria, viruses, and parasites and just makes it difficult for those pathogens to get to the skin of the fish. Slime is constantly washed away just from the process of the fish swimming or, in some cases, burrowing into the substrate. When the slime washes away, so do the pathogens. But unfortunately for the fish, pathogens evolved right alongside the fish and some of those irritants manage to hold on. Luckily for the fish, the slime is also a “living” part of the immune system with all the anti-pathogen devices that are also inside the fish, so the slime, besides slowing down the pathogen, has the ability to kill most of the offending organisms. (Many supermodels have bodyguards for that.)

Fish slime covers the entire outside of the fish, even the fins and eyes, extending into the gills. That is also the reason fish can quickly regenerate fins. If a fin is damaged, the living slime covers the damaged area, allowing the fish to send cells to the site to repair the damage. If we get an injury, it is easily infected and takes a long time to heal because the outer layer of our skin is dead, so we have to wait for a scab to form to protect the area, then we have to wait for the scab to eventually fall off before the area is healed. During that time, bacteria can enter the wound, causing infection or worse. There is a study going on that uses fish slime to treat human skin wounds.

Slime production takes energy!
Fish continually produce slime and it, like developing eggs, is a huge burden and energy drain on the fish, requiring many calories every day to form efficiently. If a fish is injured or under stress, it will produce more slime. Slime production will also increase if an irritant, such as copper, is used in an attempt to cure a parasite. Extra slime will also make it harder for a parasite to get hold of the skin of a fish and make it easier for the fish to slough off extra slime to help eliminate parasites.

Fish slime is the first—and best—line of defense a fish has. As I said, the slime is alive and just like the insides of the fish, its immune system works with anti-biological, anti-viral, and anti-parasitic substances.

Imparting immunity
These substances, just like in us, depend on an earlier infection so the immune system can recognize the offending pathogen. Some of this immunity comes from the mother and is transferred to the fry as it is developing in the womb. If this were not so, baby fish would have a very hard time surviving in the sea, as their slime coat is very thin.

Also, like us, some of these pathogen fighting substances depend on occasional meetings of the fish and these offending pathogens, which is the reason we humans need occasional injections of anti-viral or bacterial serums to protect us. Before we discovered anti-tetanus shots, many people died from minor injuries. Fish in the sea are constantly exposed to these pathogens, but in a tank, they are not, which is the reason for all the posts in disease forums. Unfortunately, there is much more energy going into curing fish than protecting fish from disease in the first place.

 

[eatbreakfast]

Lionfish, I did not come up with that. That was "Popular Science Magazine" (I added a few lines to it)

Quote: (kind of)
"Popular Science" (August 2015) there is an article about this very topic. The author states that the most germ free environment today is on the International Space Station. Everything is sterilized including the air. All the surfaces are coated with bacteria limiting coatings, even the water is treated with iodine and biocidal nano silver so the only bacteria present are the ones coming from the astronauts themselves. They can't open a window or send out for Pizza (I added that last sentence) so there is no fresh influx of microbes to balance the ecosystem. Sounds like quarantining doesn't it? ( I also added that sentence) He also states that a loss of gut bacteria correlates with many diseases and could impede longer space travel. If we lose our gut bacteria, our immune system goes dormant.
In the real world bacteria, viruses and parasites evolved right along with other organisms that help keep each organism in check. They have their enemies and friends. When we mess with the system by using antibiotics or extended periods of quarantine, or remove living bacteria from their food, we are dooming the fish to a life where they are on the verge of getting a fatal disease.
This is also the reason so many diseases are contracted in hospitals, a place where great pains are taken to keep the place clean. They are clean, so the only bacteria present are from sick people with no other bacteria or viruses to counteract them. It is now thought that people using those hand sanitizers from very young are at a higher risk of becoming an allergic toddler.
End.

Bob, I realize we don't quarantine in a germ free environment as that would be impossible, but we try to quarantine in a parasite free environment and I think that is a mistake. Unlike most people I want parasites living in my tank, yes, including velvet.
Why is it that my fish are immune? Why can I add fish any time with any disease and have no problems? I can't see the parasites or know their friends but I "think" they are happily living in my tank and have been for decades.
I always mention feeding my fish with live foods as much as possible, that is to provide living bacteria to the gut of the fish. I learned that through trial and error but lately there has been research (which I linked many times) that proves fish require living bacteria and parasites in their diet to remain healthy and immune. I wish I came up with that myself, but I didn't.
People have said our immune systems are much like fish. They are not. The only similarity to fish is that we both have mechanisms to kill certain bacteria, viruses and parasites. We humans are also covered in parasites, on our skin and in our guts.
The main defense a fish has from diseases is in their slime. Most of us don't exude slime. Well I did date a slimy girl once but I digress.

Here is something I published but I am not smart enough or good looking enough to have come up with it myself. I did a lot of research to find out all of this but my experience confirmed it for "me".
This is where we differ from fish as we don't regenerate limbs or exude slime. We also don't make our antibodies in our kidney as fish do and fish have no bone marrow as we do which is where we make most of our antibodies. Fish have anti-parisitic properties on their skin, we have tattoos, "Right Guard" and little else.
It takes much more calories in a fish to stay immune than us. That is because (as I said) fish are in water and disease organisms, especially parasites can swim better than they can fly and fish constantly eat parasites and harmful bacteria at every meal. We tend to cook our food and try not to eat rotten, live food or "each other" as much as we can. It is also because fish exude slime which washes off constantly. Have you ever tried to hold a moray eel? You can't. And if you did, you would be covered in slime as those things are full of the stuff. Pick up a hagfish, then kiss your girlfriend.

The many roles of fish slime
The first way slime protects the fish is mechanical. Slime traps bacteria, viruses, and parasites and just makes it difficult for those pathogens to get to the skin of the fish. Slime is constantly washed away just from the process of the fish swimming or, in some cases, burrowing into the substrate. When the slime washes away, so do the pathogens. But unfortunately for the fish, pathogens evolved right alongside the fish and some of those irritants manage to hold on. Luckily for the fish, the slime is also a “living” part of the immune system with all the anti-pathogen devices that are also inside the fish, so the slime, besides slowing down the pathogen, has the ability to kill most of the offending organisms. (Many supermodels have bodyguards for that.)

Fish slime covers the entire outside of the fish, even the fins and eyes, extending into the gills. That is also the reason fish can quickly regenerate fins. If a fin is damaged, the living slime covers the damaged area, allowing the fish to send cells to the site to repair the damage. If we get an injury, it is easily infected and takes a long time to heal because the outer layer of our skin is dead, so we have to wait for a scab to form to protect the area, then we have to wait for the scab to eventually fall off before the area is healed. During that time, bacteria can enter the wound, causing infection or worse. There is a study going on that uses fish slime to treat human skin wounds.

Slime production takes energy!
Fish continually produce slime and it, like developing eggs, is a huge burden and energy drain on the fish, requiring many calories every day to form efficiently. If a fish is injured or under stress, it will produce more slime. Slime production will also increase if an irritant, such as copper, is used in an attempt to cure a parasite. Extra slime will also make it harder for a parasite to get hold of the skin of a fish and make it easier for the fish to slough off extra slime to help eliminate parasites.

Fish slime is the first—and best—line of defense a fish has. As I said, the slime is alive and just like the insides of the fish, its immune system works with anti-biological, anti-viral, and anti-parasitic substances.

Imparting immunity
These substances, just like in us, depend on an earlier infection so the immune system can recognize the offending pathogen. Some of this immunity comes from the mother and is transferred to the fry as it is developing in the womb. If this were not so, baby fish would have a very hard time surviving in the sea, as their slime coat is very thin.

Also, like us, some of these pathogen fighting substances depend on occasional meetings of the fish and these offending pathogens, which is the reason we humans need occasional injections of anti-viral or bacterial serums to protect us. Before we discovered anti-tetanus shots, many people died from minor injuries. Fish in the sea are constantly exposed to these pathogens, but in a tank, they are not, which is the reason for all the posts in disease forums. Unfortunately, there is much more energy going into curing fish than protecting fish from disease in the first place.

The comparison of regenerating fins to limbs is a bit off. They can regenerate fin rays and the membrane inbetween, but this is more akin to us regrowing fingernails rather than limbs.

Slime production is it's first level of defense, but productuon is disrupted by stressors, which range from transport, temp swings, new surroundings, loud noises, dirty water, infrequent meals, bullying, and any other countless combination of stressors. The slime coat is also damaged by contact, so when a new fish is netted, the slime coat is damaged andcthis fish is in a very conpromised situation if it gets introduced to pathogens.

In aquaria, these pathogens are in a much greater density unless treated for in some way, either through a qt protocol, meds, uv sterilization, or use of ozone.

 

[Husker]

Bob, I realize we don't quarantine in a germ free environment as that would be impossible, but we try to quarantine in a parasite free environment and I think that is a mistake. Unlike most people I want parasites living in my tank, yes, including velvet.
Why is it that my fish are immune? Why can I add fish any time with any disease and have no problems? I can't see the parasites or know their friends but I "think" they are happily living in my tank and have been for decades.
I always mention feeding my fish with live foods as much as possible, that is to provide living bacteria to the gut of the fish. I learned that through trial and error but lately there has been research (which I linked many times) that proves fish require living bacteria and parasites in their diet to remain healthy and immune. I wish I came up with that myself, but I didn't.
People have said our immune systems are much like fish. They are not. The only similarity to fish is that we both have mechanisms to kill certain bacteria, viruses and parasites. We humans are also covered in parasites, on our skin and in our guts.
The main defense a fish has from diseases is in their slime. Most of us don't exude slime. Well I did date a slimy girl once but I digress.

Here is something I published but I am not smart enough or good looking enough to have come up with it myself. I did a lot of research to find out all of this but my experience confirmed it for "me".
This is where we differ from fish as we don't regenerate limbs or exude slime. We also don't make our antibodies in our kidney as fish do and fish have no bone marrow as we do which is where we make most of our antibodies. Fish have anti-parisitic properties on their skin, we have tattoos, "Right Guard" and little else.
It takes much more calories in a fish to stay immune than us. That is because (as I said) fish are in water and disease organisms, especially parasites can swim better than they can fly and fish constantly eat parasites and harmful bacteria at every meal. We tend to cook our food and try not to eat rotten, live food or "each other" as much as we can. It is also because fish exude slime which washes off constantly. Have you ever tried to hold a moray eel? You can't. And if you did, you would be covered in slime as those things are full of the stuff. Pick up a hagfish, then kiss your girlfriend.

Hmm... I would be leery of wanting parasites in quarantine as a means of promoting or boosting immunity. If the fish have been exposed to the parasites, they should have cellular and antibody-mediated immunological memory. Yes, this does wane in some circumstances over time. However, the mechanisms of immunologic memory waning are not fulling understood. Vaccines against some antigens can provide memory for a lifetime without subsequent exposures (or clinical boosts). There are several hypotheses for how this might be accomplished: one being the sequestering of antigen in the lymph nodes by special dendritic cells (look up follicular dendritic cells). In contrast, chronic antigenic exposure can also be deleterious. The phenomenon of "immune exhaustion" is well documented (although is recently undergoing some revision in semantics due to new data). Chronic infections, such as HIV in humans, can reduce antiviral immunity due to long term antigenic stimulation (this is independent of loss of immunodeficiency due to loss of CD4 T cells). Immune exhaustion is actually an evolutionary adaptation by our immune system-- you don't want to develop an immune response against things that are sticking around permanently, because they might not be too bad. In fact, in chronic infections, chronic immune responses are often more problematic than the microbe itself.

Additionally, the idea of quarantine is predicated on the notion that the fish are stressed and immunosuppressed. In AIDS patients, it doesn't matter if they have previously been exposed to cytomegalovirus or pseudomonas, the depletion of their immune system renders them susceptible to these otherwise innocuous infections. Another example is in cattle, called Bovine Shipping Fever (or Bovine Respiratory Disease). In this situation, stress in the form of glucocorticoids is a strong immunosuppressant. These cattle can get very sick and die from infections that are otherwise not problematic, such as bovine herpes virus (BHV).

The differences you point out between fish and human immune systems are true, but they don't necessarily equate to functional differences. The site of maturation of antibody producing cells is interesting, but I'm not sure the relevance to anti-parasite immunity. You could also consider our keratinized skin and mucosa to be analogous to fish slime coats.

Either way, I'm a huge fan of your long term tank and philosophy, Paul. One thing is true: you are demonstrating important distinctions between what happens in the lab and what happens in the real world, full of complexities. This has been a problem in translational medicine for some time, where failures in the clinic are unexplainable based on success in the laboratory. In your case, your success in the home aquarium might be initially unexplainable. There's nothing wrong with creating your own luck.

 

[Areseebee]

Lionfish, I did not come up with that. That was "Popular Science Magazine" (I added a few lines to it)

Quote: (kind of)
"Popular Science" (August 2015) there is an article about this very topic. The author states that the most germ free environment today is on the International Space Station. Everything is sterilized including the air. All the surfaces are coated with bacteria limiting coatings, even the water is treated with iodine and biocidal nano silver so the only bacteria present are the ones coming from the astronauts themselves. They can't open a window or send out for Pizza (I added that last sentence) so there is no fresh influx of microbes to balance the ecosystem. Sounds like quarantining doesn't it?

I can't stress this enough. Quarantine is NOT sterile. It's not the same thing, the same concept anything.

He also states that a loss of gut bacteria correlates with many diseases and could impede longer space travel. If we lose our gut bacteria, our immune system goes dormant.

It's bigger than the immune system, gut microbiota influences everything from fertility to life span, health to how we respond to drugs in nearly all model organisms we check. As far as I know this largely has to do with their metabolism breaking down particular compounds and producing less toxic or more useful metabolites. I am totally on board with this being important in our fish.

 

[Tim Gentry]

Is it necessary? No. If you don't enjoy losing most most of your fish to Ich, Marine Velvet, Brooklynella etc. then YES, it's necessary. I learned the hard way and I'm not going on to lose a whole tank of fish because I intrdoduced new one without quarantining it anymore. I have a 10g quarantine tank now.

 

[Husker]

I would love to read a paper from you Husker. It is something I have yet to learn, and I am not sure if we as a community will get the chance to hear from someone who can speak about fish immunology!

Anyway, if anyone else wants to learn about fish health and how our friends in our glass boxes react when stressors and disease come their way, please come throw your vote into the ring to signify support so we can read what Husker can teach us.

You would be surprised! The journal Fish and Shellfish Immunology has really taken off in the past few years. There are many groups focusing on the immune systems of fish as of recent. However, I would venture 80% of the papers are in either carp, trout, salmon, or Danio rerio. My colleagues would have quite the laugh fest if they knew people were asking for my "expertise" in fish immunology..ha.

 

[Paul B]

Husker, thank you for posting. I would also be Leary of quarantining with parasites, but I don't believe in quarantining so in my case, that doesn't matter. I am not opposed to putting a new fish in a separate tank for a few days if I feel it has some sort of problem that I can't see to in my reef. I often buy fish with infections or parasites because I can get them for very cheap or free. Sometimes those fish die and it is just easier to remove them if they are not in my reef and of course I can cure them easier if they need curing. If the fish just has some parasites I have no problem just putting that fish in my reef unless of course the thing is in the process of getting last rites and it obviously will not make it.
I am sure you are correct in that resistance to some diseases and parasites last a lifetime, but not in fish for the most part. If it did, we would have no need for disease forums and if you look, you will find more fish disease posts than anything else. With a very few exceptions all of our fish were collected in the sea and at that time they all had immunity. It is our fault if we allow that immunity to wither away.
As for lymph nodes, fish don't have any. I wasn't sure about that so I had to look it up:

Quote:
RETICULOENDOTHELIAL SYSTEM

Fish do not have lymph nodes. Phagocytic cells are present in the endothelial lining of the atrium of the heart and in the gill lamella. There are no phagocytic cells (Kupffer cells) in the liver. Melanomacrophage centers are present in the liver, kidney and spleen. Melanomacrophage centers increase in number during disease or stress.

The fish thymus is the central lymphoid organ. This organ is located subcutaneously in the dorsal commissure of the operculum.

Fish have the ability to produce specific immunoglobulins (IgM only) and have both delayed and immediate hypersensitivity. Fish have the ability to produce virus neutralizing, agglutinating, and precipitating antibodies. Both B and T lymphocytes are present.
(I got that here: http://www.cichlid-forum.com/articles/biology_of_fish.php)

You could also consider our keratinized skin and mucosa to be analogous to fish slime coats.

I am not sure about this but you would know much more about it than I would.
I did however find this in that link I added:

INTEGUMENT

Fish do not have a keratin layer over the epidermis. A cuticle composed of mucus, mucopolysaccharides, immunoglobulins and free fatty acids covers these animals. The epidermis is composed of a stratified squamous epithelium of variable thickness (4 20 cells thick). The outermost epidermal cells (Malpighian cell layer) retain the capacity to divide. Other cells present in the epidermis are goblet cells (responsible for secreting the cuticle), large eosinophilic club cells or alarm cells (present in most species of fish), eosinophilic granular cells (unknown function), leukocytes and macrophages.

The dermis is composed of an upper stratum spongiosum and a deeper stratum compactum. Numerous melanophores, xanthophores, and iridophores (give fish their silvery color) are observed scattered throughout the dermis. Scales are calcified plates originating in the dermis and covered by the epidermis. There are two types of scales: ctenoid scales and cycloid scales. Ctenoid scales of elasmobranchs have spicules extending from the external surface giving these fish a rough sandpaper like texture. Cycloid scales of teleost fish have a smooth outer surface and are laid down in concentric a ring that makes them useful in determining the age of some fish. Scales also represent a source of calcium for fish; some fish will utilize the calcium in the scales in preference to the calcium in their skeleton during times of starvation or prespawning activity.

 

[Gwitness]

So let's just say your MAIN tank has parasites and the current fish are living healthy and side by side with the parasites....

What if you quarantined every new fish that you bought and treated them with copper and prazi pro for 1 month......if done right, during that 1 month they would have diseases/parasites gone...the fish would be eating good by then and should have a built up immune system before it goes into the main tank....

Obviously, the main tank will have parasites because the existing fish are in there, but wouldn't the new fish that are being added to the main tank have a much higher survival rate and able to fight off existing ick parasites in the tank since they have been eating healthy in a parasite/disease free environment for a month?? I was thinking they would kind of have a head start to be able to fight off the existing parasites easier because they are coming into the main tank parasite/disease free and with a good immune system from eating for a month in quarantine??

Let's just say during the entire quarantine time I treated them with the medicine and fed love food like paul b says in quarantine for that month....

I'm just curious, but I'm assuming survival rate would be way higher for the new fish and wouldn't you limit any NEW disease out break since every new fish is "disease free"

 

[Paul B]

Areseebee, I am not opposed to quarantining because I believe it is sterile. I do not. I am opposed to quarantining "for an extended period" like 72 days for a couple of reasons. The first reason is that stressed fish that we buy should not be stressed further by being in a mostly bare, mostly smaller tank, that is my first concern. Look up on this forum how many fish die in quarantine. My second concern is that (and I may be totally wrong) I don't know how long the fishes natural immunity lasts without the presence of parasites. Then the fish are introduced to a tank that is sterile as far as "Parasites go". Not sterile as far as bacteria goes as we can't do that even if we wanted. But a fish living in a parasite free tank would at some point lose it's natural parasite fighting ability. A fish in that condition can't be fed live foods, and can't be with NSW unless it is sterilized. Everything added to it's tank must be parasite free so any corals , rocks or crustaceans must be fully cleaned of parasites for as long as the tank is set up. You can not have a natural system like that. Natural means somewhat like the fish had in the sea. Of course we can't duplicate the sea, but we can try.
I live near the sea so I use some NSW, mud, amphipods and foods from the sea. If I lift a rock in my tank I will see the entire food chain from tiny worms, amphipods, copepods, starfish, tiny clams, shrimp and everything from the sea as that is natural. A sterile tank (in that respect) is not as healthy, IMO.
But if you can keep your fish alive for their entire lifespan, "and" they are spawning, that is all you can ask for. It's like people, if we lived in a town where everyone dies as teenagers, we may not want to live there, but that is the way many tanks run. With fish living 4 or 5 years. 4 or 5 years is the lifespan of some seahorses and pipefish but almost all fish live much longer and some forty or fifty years. Almost All clownfish live into their thirties given the correct conditions. Lifespan is the determining factor if we are successful or not. And I presume we want to be successful.

Is it necessary? No. If you don't enjoy losing most most of your fish to Ich, Marine Velvet, Brooklynella etc. then YES, it's necessary. I learned the hard way and I'm not going on to lose a whole tank of fish because I intrdoduced new one without quarantining it anymore. I have a 10g quarantine tank now.

Tim, it is necessary for some people, not all. My reef is 46 years old and my oldest fish is 25. Almost all my fish die of old age and the rest jump out. My fish never get ich, velvet, brooklynella or anything else. I attribute that to the presence of those diseases you mention being in my tank so my fish stay immune to them. But it is not for everyone that is why the title of my book is
"The Avant Garde Marine Aquarist" Avant Garde means :

The avant-garde (from French, "advance guard" or "vanguard", literally "fore-guard")[1] are people or works that are experimental, radical, or unorthodox,[1] with respect to art, culture, and society.[2][3][page needed] It may be characterized by nontraditional, aesthetic innovation and initial unacceptability,[4]
In no way do I mean for anyone to follow my example, I am merely stating it because the title of this thread is: "Is a Quarantine Tank essential?"
I am answering that. For most people it is, but for some, it is not.

 

[Paul B]

So let's just say your MAIN tank has parasites and the current fish are living healthy and side by side with the parasites....

What if you quarantined every new fish that you bought and treated them with copper and prazi pro for 1 month......if done right, during that 1 month they would have diseases/parasites gone...the fish would be eating good by then and should have a built up immune system before it goes into the main tank....

Obviously, the main tank will have parasites because the existing fish are in there, but wouldn't the new fish that are being added to the main tank have a much higher survival rate and able to fight off existing ick parasites in the tank since they have been eating healthy in a parasite/disease free environment for a month?? I was thinking they would kind of have a head start to be able to fight off the existing parasites easier because they are coming into the main tank parasite/disease free and with a good immune system from eating for a month in quarantine??

Let's just say during the entire quarantine time I treated them with the medicine and fed love food like paul b says in quarantine for that month....

I'm just curious, but I'm assuming survival rate would be way higher for the new fish and wouldn't you limit any NEW disease out break since every new fish is "disease free"

I would say you may be correct, but I am not sure it would have much impact because I add fish now with no copper and I have no problems. I have no problem with , (and I mention this several times even in my book) quarantining fish for 30 days. I would have a problem with 72 days but I think 30 days would be fine. I know I mentioned my book a few times and I am sorry. I don't mean for anyone to buy the book I am just trying to prove that this is the way I think. Again, in my book I write that if I were to start a new tank, I would quarantine everything in copper for two weeks. So I am not opposed to that. As long as I have parasites in my tank so that the fish can stay immune from them. I also say, that if a new fish is added and it becomes covered in parasites, it should be removed and treated in copper as not all fishes immune systems will protect them especially if the new fish has not eaten in a long time and is already in bad shape.

 

[Gwitness]

I would say you may be correct, but I am not sure it would have much impact because I add fish now with no copper and I have no problems. I have no problem with , (and I mention this several times even in my book) quarantining fish for 30 days. I would have a problem with 72 days but I think 30 days would be fine. I know I mentioned my book a few times and I am sorry. I don't mean for anyone to buy the book I am just trying to prove that this is the way I think. Again, in my book I write that if I were to start a new tank, I would quarantine everything in copper for two weeks. So I am not opposed to that. As long as I have parasites in my tank so that the fish can stay immune from them. I also say, that if a new fish is added and it becomes covered in parasites, it should be removed and treated in copper as not all fishes immune systems will protect them especially if the new fish has not eaten in a long time and is already in bad shape.

Okay that makes sense for sure....and it would also help prevent any big disease outbreak if new fish are treated, unless the disease came in on a coral or a snail or something.

 

[Husker]

Fish don't have many lymph nodes, but the cellular interactions which take place in the lymph nodes still take place. Mammals just have more of an anatomical niche for such interactions ("why?" is a very fascinating question). Fish are not less evolved than mammals. In fact, fish have been evolving along their lineage in their environment for much longer than mammals. It is just a little funny to realize that when mammalian immune systems are seemingly so much more "advanced."

I think it would be really interesting to see if fish antibody titers wane quickly when they are put in sterile conditions. This would support your notion that quarantining fish does more harm than good unless your tank is completely sterile. If anybody can find any published studies on this, I would love to hear them: a requirement for persistent antigenic exposure to maintain long term antibody titers in fish. If not, we have a pretty large Danio rario breeding colony going. It would take some time, but I think we could set up some experiments to test the duration of antibody responses against experimental antigens.