Diseases appear "out of nowhere"

[LaloJ]

I'm rescuing a blue tang and a couple of velvet ocellaris clownfish in my qt tank, they are not fish for me so I used my qt tank to condition them and feed them the best I could, and although they were eating very well unfortunately after a week the blue tang started with velvet and immediately everyone was covered with white dots, so they all went to a hospital tank with copper, one of the clowns already died, but the point I want to touch on today is how these parasites can arise "of nothing". I acquired the fish from a "reliable" distributor, I see that this is not the case, I had forgotten the terrible quality of fish that we have in Mexico, that is already starting on the wrong foot, that is why it must be quarantined without fail and that made me remember my beginnings when the fish got sick after a few days and died of velvet, at least it happened on 4 occasions (with a fallow period), so I quarantine the fish for 3 months for several years, however I never use medication unless necessary and on some occasions the fish have subsequently developed diseases, some internal parasites or sometimes the fish after many months have developed cryptocarion or bacterial infections, which led me to think if these diseases can really "trigger out of nowhere" despite spending 90 days in qt and several months later in the main tank. How can a fish develop internal parasites a year later? Always feeding a good variety of foods, I'm not questioning the effectiveness of qt tanks, I'm just talking about how frustrating it's to have a good job conditioning these fish for months and then "out of nowhere" you see white spots on them, white feces or white spots on their fins, it's completely frustrating and I feel that way now, I'm planning my next 150 gallon tank, I'm looking for equipment and everything I need to build this system that I have wanted for years but this has made me I stopped to think twice or as many times as necessary, I'm sorry if this post is pessimistic, it was not my intention.
Greetings.

 

[Timfish]

Why do apparently healthy people develop diseases? Organisms can have "subclinical" issues that may be unobservable and can take significant portions of thier life expectancy to develop and cause obvious problems.

Just like with people, poor diet and/or stress can reduce a fish's immunity and resistance to pathogens and parasites. (Most fish I've seen in hospital or quarintine tanks look or act stressed in the sparse and unatural conditions, I try to make mine as natural for the fish as possible and FWIW I've stopped using copper preffereing the less stressful use of over sized UV sterilizers in QTs.)

As far as parasites in aquaria, keep in mind it's impossible to irradicate every kind or species of parasite.

SPeaking specifically to "ich", it only takes a few "larva" in a drop of water or a cyst attached to a solid surface and transfered to a new system to infect or reinfect a system.

 

[ISpeakForTheSeas]

is how these parasites can arise "of nothing".

How can a fish develop internal parasites a year later?

There are two possible reasons why these things can seem to appear out of nowhere:

1 )The diseases/parasites were there all along and the issue just wasn't bad enough to show itself visibly, typically because the fish were healthy enough that their immune systems were able to keep it mostly at bay (this is why fish can go years seemingly perfectly healthy, then have a stress event and break out with ich under ich management methodologies - the stress suppresses the immune system, and the disease/parasite is able to take advantage of the issue).

2 )The fish were actually healthy but something added to the tank brought the diseases/parasites in (fish are the most common carrier of disease/parasites, but anything wet - inverts, corals, macroalgae, live rock, etc. - can bring them in as well).


This is why I'm of the belief that aquarists really need to commit to either 100% ich management or 100% treatment and QT - you can either prevent serious disease/parasites from ever entering the tank (treatment and QT) or you can keep the fish healthy enough and the tank conditions good enough that they thrive even with the diseases/parasites in the tank (ich management).

[Preferably, care and tank conditions are good enough to keep the fish healthy regardless of which method is chosen, but for many people, particularly those newer to the hobby, treatment/QT is likely easier to find success with - this is why I'm personally a fan of recommending people get pre-QT'd fish and inverts where possible and just QT'ing everything else themselves, but not everyone wants to do that].

 

[LaloJ]

I have been practicing qt for years, I have separate elements such as a siphon, buckets for water changes and things like that separately, nothing is used in another qt tank and much less in the main tank, and for example when there are diseases that occur in qt I simply undo the biological material and sterilize and start again with biological material that is in my sump. I'm sure that the quality of the fish they sell us here greatly influences the success. These fish can also get sick along the way and appear with white spots when they arrive at their destination. If that is the case, then do you recommend medicated quarantine?? I had thought about using paraguard which is supposedly milder than cupramine but many do not recommend it, apparently it's not effective. Given the quality of fish in my area, some aquarists have chosen to do qt in my tanks, this works like a business for me, I'm hospitalizing another blue tang with cryptocarion now, I really don't want to fail doing this even though at times it seems frustrating , Thank you for your answers.

 

[ISpeakForTheSeas]

I have been practicing qt for years, I have separate elements such as a siphon, buckets for water changes and things like that separately, nothing is used in another qt tank and much less in the main tank, and for example when there are diseases that occur in qt I simply undo the biological material and sterilize and start again with biological material that is in my sump. I'm sure that the quality of the fish they sell us here greatly influences the success. These fish can also get sick along the way and appear with white spots when they arrive at their destination. If that is the case, then do you recommend medicated quarantine?? I had thought about using paraguard which is supposedly milder than cupramine but many do not recommend it, apparently it's not effective. Given the quality of fish in my area, some aquarists have chosen to do qt in my tanks, this works like a business for me, I'm hospitalizing another blue tang with cryptocarion now, I really don't want to fail doing this even though at times it seems frustrating , Thank you for your answers.

Personally, I favor medicated QT as recommended here on R2R (see the Current Quarantine Protocol link in the last quote below), but a lot of people favor ich management - which you decide to do is up to you.

generally speaking if a fish makes it through QT it’ll be fine being transferred to the DT (the only exceptions I can recall hearing about involved instances of established fish aggression against the new fish).

That said, there are basically three camps that I’ve seen with QT:

-Full, medicated QT (the timeframe for this can vary, but Jay Hemdal’s 2023 protocols suggests 64 days); this is likely the most stressful option, but the thought for this is basically that disease can’t wipe out your tank if it isn’t in your tank. Some people believe this weakens a fish’s immune system and may lead to them dying relatively young.

-Observational QT (I generally see this from reefers in places where it’s harder to get fish meds); this option is probably still stressful for the fish, but it seems to be more about avoiding particularly deadly diseases (such as velvet) or knowing in advance what you’re allowing into the tank. This method carries a lot of the same risks as no-QT (see below), but it can give a heads-up about issues new fish may have/introduce.

-No QT; this avoids the stress of being moved between tanks, but I feel like Paul B’s comment above is a pretty accurate description here. The thought here is that a healthy fish with a healthy immune system won’t die except from old age. Basically, this method can work if you’re able to provide good water, good food, and a good environment for the fish. Most newcomers to the hobby are probably not capable of that when they start, and when the fish isn’t healthy/is too stressed (such as because of inadequate water, food, or environment), them any diseases they’re carrying flare up and can take them out (hence why the disease forum here is full of no-QT tanks getting wiped out by diseases). This method does carry the risks that 1) a deadly disease like velvet may come in and wipe some or all of the fish in the tank out unexpectedly and 2) if a stressful event (such as a bacterial bloom, for example) happens unexpectedly, you may face a disease outbreak in the tank at the same time. Jay Hemdal has some posts about other potential weaknesses of this method here on R2R too, but these are the most important in my mind for most people to be aware of.

So, for most people a properly done, full, medicated QT is probably the safer route to go with when just starting out - honestly, this is why I’m personally a fan of pre-QT vendors, as they have a pretty good track record of delivering disease-free fish (meaning that sub-optimal care like the average newcomer is likely to unintentionally give the fish is less likely to kill it), and it’s hassle-free for the buyer.

Again, all of these methods when done properly can work, and they all have some pros and cons, but those are my two cents on the matter.

If you dislike the copper treatments available for ich where you're at, you can also put the fish through hyposalinity (1.009) instead. If you have access to chelated copper meds like Coppersafe Copper Power, those are effective while still being milder than Cupramine.

if you want to treat ich effectively, you need either copper medication (chelated copper like Coppersafe or Copper Power at 2.25-2.5ppm for 30 days after the last ich trophonts disappear is recommended) or hyposalinity (drop your salinity to 1.009 and keep the tank at that salinity for 30 days after the last signs/symptoms of the disease disappear), neither of which are reef-safe. There is no effective, reef-safe treatment for ich at the moment (at least not one that I've heard of).

To prevent the tank from getting ich again, you would get the fish out and treat them (either with copper or hyposalinity - see below for info on both), then QT anything "wet" that goes into your tank (or near it) for a minimum of 45 days at 81F; 60-76 days (especially if at lower temps) is recommended. That means quarantining fish, inverts, coral, rocks, sand, macroalgae, etc.

For copper treatment and hyposalinity:

Hyposalinity

Hyposalinity Jay Hemdal 2021 This term refers to a long-term bath treatment for marine fishes in which the salt content of the water is lowered and held below the point that certain parasites can survive. The salt level reached, and the time of the treatment are the two variables...

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For future quarantines:

Current Quarantine Protocol

2023 Quarantine Procedures Jay Hemdal David Scarborough Protozoans (Cryptocaryon/ich, Amyloodinium/velvet) and Metazoan trematodes/flukes are by far the most common parasites found on newly acquired fish. A carefully managed quarantine process can effectively eliminate these parasites before...

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Biosecurity

A short introduction to aquarium biosecurity

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