I read Paul's post about his method (no quarantine") and I liked it. It sounds logical and it's the way nature works. However, I see that there are way more people who quarantine fish than those who don't. So then his method is not welcomed? And it's not right? What do you think?
(
https://www.reef2reef.com/threads/the-other-way-to-run-a-reef-tank-no-quarantine.534274/)
So here's the thing.... QT or not QT is absolutely a preference. But most of the information you're getting is anecdotal, including Paul B's (for whom I have a lot of respect as he's on my local forum as well). It's individual hobbyist's experiences, rather than science. (For background, I worked in marine science aquaria for years and then in rescue and rehabilitation of marine mammals, but I am
not a pathologist).
Let's look at the science.
In the wild, animals are exposed to all kinds of pathogens, good and bad. Balances are not struck in individual animals, rather the Darwinian process through a group. A group of animals get sick, some die, some survive. The ones that survive may have an immunity built up to that particular disease that they MAY then pass along to offspring. If the immunity is passed along, then the offspring are less likely to die from the disease, but it may not prevent them from contracting it. Eventually, the disease may also evolve through mutation so that the immunity is no longer working, and the process repeats. But make no mistake, plenty of animals get sick and/or die during this process.
Under Paul B's method (or lack of method as he describes), he's relying on the animal's natural immune systems to combat sickness
resulting in death. He's not eradicating the diseases from his system, rather relying on the natural immune system to fight off diseases. While this may work for some animals, it still assumes that there is disease(s) in the tank and that the animals he's putting in either have a natural immunity to the disease(s), or can acquire one. There are several assumptions in this method:
1. The goal is to not have fish
die from disease, rather than the goal being not to get sick.
2. That all fish will have been exposed to and thus have a natural immunity to, or can develop a resistance to the various disease(s) in the tank.
3. That fish coming from different regional locations or different types of locations (aquaculture v. wild) will all carry similar diseases or have immunity to the same diseases.
4. That fish getting sick is not problematic.
5. That fish dying from the lack of method is not problematic.
6. That new fish coming into the system will not introduce a disease to the DT to which the system has no immunity.
Let's examine those individually (numbers correspond).
1 & 4. Is this your goal? Are you prepared to handle a sick fish, and do you know what to do? Do you know at what point the fish's life is endanger, versus just needing to supplement and support their immune system? Do you have the ability to catch that fish if you need to get it out of your DT? Do you have meds that are safe for your tank based on treating in your DT?
@Paul B obviously does, and knows how to handle this in his tank. Not everyone does or will (I certainly don't!).
2, 3, & 6. Not all diseases are the same, and even the same disease can have different strains. To make this easy to think about, think about the variations within a single species of fish based upon whether it's caught in Hawaii, Maldives, or Fiji. They're not the same, and neither are the diseases that they naturally carry or have been exposed to. So their immunity to ich may be to the particular strain that occurs naturally in their geographic location, but that same immunity may fail when a different strain of ich is introduced. Another example is Montezuma's Revenge, when they tell American tourists not to drink the water in Mexico for massive diarrhea that can occur as a result of exposure to pathogens in the water. Locals don't have the problem, but tourists have no immunity. Will it kill you, probably not, but if you're already immuno-compromised or weak, maybe. Your tank may be balanced until you introduce a new strain of disease from a different region. Therefore, your Lyretail Anthias from the Maldives may carry a particular strain of ich to which it easily tolerates. But the male kills off his females, and you buy some other anthias females from Indonesia and introduce them into the tank. Suddenly, your male starts showing signs of ich. Is it that his immune system is under attack and this is his own strain of ich just showing up, or is this a strain of Indonesian ich to which he has no immunity? If he dies, what are your assumptions about the death? If he lives, do you make the same assumptions? How do you know which of those possibilities has occurred? Most of us as hobbyists do not have any way of knowing.
5. Fish dying is always a problem...it's about how much of a problem. How many fish died? Which fish died? How much did you like that particular fish (your kid named it, your spouse's fav, the one that ate out of your hand)? How much did that fish cost (a blue chromis v. a peppermint angel)? So much of these questions are very personal in nature and can't be answered by anyone but the aquarist themselves.
To me, this is the problem with a NO QT method. You're playing a probability game with disease, but most of us have no true knowledge of fish disease or immunity. Therefore, at some point, the probabilities will win out and you'll lose fish(pl). How many and how much it bothers you is the real question.
Another point to look at is how public aquaria do it, since their livelihood is based on massive stocks of fish, and the loss of any fish may devastate their display. These facilities almost always QT their fish. They don't want a small chromis to bring in a disease that kills their whale shark or wipes out their endangered species.
I won't bother to write up the benefits of QT because I believe
@Humblefish has done a great job on that.
