Disease eradication vs. Disease management (new)


Dr. Fish
Premium Member
This article expands upon the Ich eradication vs. Ich management thread I wrote. It takes other diseases - such as Velvet, Brook, Uronema, Flukes, Bacterial Infections - into consideration; and discusses the best strategies for preventing vs. managing all pathogens commonly found in a saltwater aquarium.

Disease eradication - Simply put, this means doing everything possible to keep diseases out of your display tank (DT). That can only be accomplished by utilizing a strict quarantine (QT) protocol as outlined here: How to Quarantine. It is very important to QT each & every fish, including your very first one, if you wish to avoid Ich, velvet and other diseases in your DT.

It is also important to QT all corals/inverts as discussed here: Coral/Invert Quarantine Time Frames

While unable to host ectoparasites the way fish do, corals/inverts are still able to "œcarry" fish diseases in one of two ways:

1. Free swimmers inadvertently attached if the coral/invert was taken from infected water.
2. Tomonts encysted to the animal, which can occur if the coral/invert was previously housed in an infected tank.

Why choose disease eradication?

Most fish pathogens are waterborne transmissible, meaning once an infected specimen has been introduced into your DT the disease will likely spread to all your other fish. Some fish may show symptoms and even succumb, others will be asymptomatic carriers. Ich and velvet trophonts drop off a fish, and become tomonts which encyst to rocks, sand, corals, glass, plastic and other hard surfaces. So, the parasites are now in your tank as much as they are on your fish. And the only way to get rid of them (in most cases) is to catch all the fish, quarantine/treat them, and go fallow in the DT: Fallow periods: Going Fishless

I personally chose disease eradication, because I got tired of "œdisease management" being a part of my aquarium husbandry. There's enough to do in a reef aquarium on a daily basis without adding "œbattle fish parasites" to the list. :p

The cons of disease eradication are somewhat obvious. In addition to having to setup & maintain a QT (or multiples), not being able to add your newly purchased fish directly to the display tank (DT) is a major buzz kill. QT does zap some of the "œthrill" out of the hobby.

What if I already have a disease (such as Ich or Velvet) in my tank?

There is no easy way of dealing with this (if you want to be completely rid of it.) You have to catch ALL of your fish, and QT/treat using a medication listed here which addresses the disease(s) you are trying to eliminate: Medications and Treatments.

This link outlines how to setup the quarantine tank: How to Quarantine.

The DT itself must be left fallow (fishless) for a predetermined amount of time: Fallow periods: Going Fishless. (In most cases 6 weeks - 76 days depending upon your tolerance for risk.) ** Note ** The two exceptions to the fallow periods are Trichodina & Uronema, which are "œfree living" parasites that do not require a fish host. They can subsist off bacteria, dead tissue and (mainly) detritus. So, going fallow will not eradicate these two pathogens. :eek:

Corals/inverts cannot host (the way fish can), so they can be left in the DT during the fallow period. (y) You must be wary of cross contamination during the fallow period, avoiding anything wet (including hands) when going from QT to DT (or vice versa). Aerosol transmission is another concern, so it's best to house your QT at least 10 feet away from the DT. More info on that here: Aerosol transmission.

Disease management - This method involves just managing the presence of diseases, instead of eradicating them. You know you have Ich/velvet, etc. in your tank or are willing to risk it by forgoing QT. Despite how strongly I advocate disease eradication these days, I employed disease management for almost 30 years. I found the key to success was keeping the overall number of parasites down, while simultaneously boosting the fishes' immune systems to deal with the parasites that survived. Let's examine some of the ways to accomplish this:

* Utilize the biggest UV sterilizer you can fit/afford (and ensure the flow rate is slow enough to kill parasites). While a UV will probably never "œzap" all of the nasties, it will keep their numbers down so fish can better cope with the ones remaining in the water.
* There are several other tools which can be used for disease management purposes: A diatom filter, ozone, Oxydator, in-tank H2O2 dosing are all options to consider.
* Boost your fishes' gut microbiota and immune system through proper nutrition. There are many ways to do this:

1. Primarily feed live foods & high quality frozen seafood, not just flake & pellets. Pods, rotifers, baby brine shrimp, blackworms and white worms are all good live food options. Frozen foods I recommend include: Mysis shrimp, clams, oysters, scallops, calanus, perch, whitefish and fish eggs. (A member of my local forum posted this homemade food recipe.) If you don't have access to these ingredients where you live then buying LRS Foods (or similar) might be a more practical option.
2. Consider using foods with probiotics added to them (LRS wins here again), and/or food soak Beta-glucan + vitamin supplements such as Selcon, Zoecon and Vita-Chem to further enhance health. Omega 3 fish oil is a great (and cheap) soaking alternative.
3. Feed nori, as that is loaded with vitamins (especially iodine).

* Stay on top of your aquarium husbandry! Maintain pristine water conditions, stable parameters and avoid fish that are likely to fight. Poor water quality, fluctuating parameters and aggression from other fish may "œstress" a fish out, lower his immune system and make him more susceptible to disease.
* Choose your fish wisely. Avoid fish which are known to be more prone to disease (e.g. angels, butterflies, tangs) and instead stock fish which are typically more disease-resistant (e.g. blennies, cardinalfish, clownfish, gobies, rabbitfish, wrasses). Do your homework and research fish that have thick mucous/slime coats that protect their skin from attacking parasites. Also, only buy from reputable sources, and don't buy fish that look diseased/damaged, won't eat or who share water with diseased fish. (Remember most LFS have their tanks all plumbed together.)
* No discussion of "œdisease management" can be had without mentioning garlic. This topic is often debated, and I honestly don't know whether or not soaking garlic in fish food helps with Ich & other parasites. I have seen it work as an appetite stimulant, so that might help right there. However, I'm less confident in its ability to boost a fish's immune system. Another theory is that garlic leaches back out of a fish's pores, and that makes the fish an undesirable host for parasites/worms. While there is no scientific evidence supporting anything beneficial, studies have been done linking long-term garlic use with liver damage in fish. Therefore, I only use garlic on an as-needed basis when a fish refuses to eat.

A fine example of utilizing proper nutrition to keep the bugs away is Paul Baldassano's (aka @Paul B) almost 50 year old aquarium. Paul keeps his fish in "œbreeding condition" by feeding live foods (blackworms, white worms), clams and other shellfish. Most of his livestock live to be a ripe old age and some of his fish spawn on a regular basis. I have a tremendous amount of respect for Paul and highly recommend this book written by him: The Avant-Garde Marine Aquarist

Pros & cons (final thoughts):

One upside of practicing disease management is obvious: Not having to QT. I get it; I really do. It's exciting to make the rounds of the local fish shops, find that "œperfect fish" and then add him to your DT. After all, having fun is what a hobby is supposed to be all about. What's fun about adding a fish to a bare bottom QT with PVC elbows? :confused:

However, the downsides are numerous. All it takes is one "œstressor event" to possibly undo years of disease management. By stressor event, I mean something like a prolonged power loss, ATO malfunction, heater sticks, fish fighting, etc. Anything that stresses a fish out and lowers the natural immune system. Sometimes Ich, velvet, brook, etc. will capitalize on these events by overwhelming a fish's immune system, and fish start dying. Also, secondary bacterial infections are common in fish with preexisting parasitic or worm infestations. All it takes is a tiny hole left by a feeding parasite trophont or worm to be the "opening" harmful bacteria will need. These bacterial diseases sometimes prove to be more virulent than the parasites (especially if caused by gram-negative bacteria), and can ultimately be what kills the fish.

Disease management is more of a "œlearn as you go" process, which is why experienced hobbyists often fare better than newbies. There is also some anecdotal evidence that mature aquariums afford the fish better protection from diseases than newly setup ones. For me personally, disease management just got to be too stressful. The stress of seeing the white dots, wondering if today was going to be the day it finally caught up with me, or if the fish that just died was a result of Ich/velvet or something else. Losing too many fish under "œmysterious" circumstances is what finally led me to choose disease eradication.


New member
I found that Cryptocaryon can be managed and eventually even eradicated by keeping stress levels low for the fish and not adding anything new to the system for at least a year.
This is actually very much in line with all the research results I've found so far.

Though I would never attempt to go this route with something as fast killing as Amyloodinium.

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New member
Velvet is the worst disease

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Believe it or not but there are far worse things you can get into your tank:
- Uronema: once it's in a system the only way to get rid of it is a complete sterilization, basically killing everything and soaking everything in bleach for good measure.
- Mycobacterium species (fish tuberculosis), not only deadly for fish and not easy to eradicate but also quite dangerous for humans (fish-handlers disease)
- Vibrio, flesh-eating bacteria. Same as above and even more dangerous for humans. Often confused with Uronema as initial symptoms on fish can look the same.
- Ichthyosporidium, a fungal infection of internal organs which is rather rare in saltwater but not so rare in freshwater. It's absolutely devastating for freshwater fish farms and the thing that gives them the most sleepless nights. In saltwater fish you usually get it via infected freshwater feeder fish.

In relation to those, Velvet is rather easy to handle.

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