A. Colorni*, A. Diamant
Dis Aquat Org 65: 177–180, 2005, Published June 30
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Under perturbed environmental conditions, specificity between fish hosts and their parasitic fauna often breaks down (Rohde 1982, Thoney & Hargis 1991), and the potential aggressiveness of a parasite towards an unusual host is expressed (Colorni 1994).
So if you suspect a fish to have parasites, then you must take care not subject that fish to a tank which has no well-developed microbial community. Such a tank is inherently unstable.
This makes a typical QT (or quarantine) tank the perfect environment to bring out the worst, most aggressive patterns of behavior in a parasite – a parasite on a fish which you know to have been super stressed.
Putting a fish in this position can practically force you to use medication(s) to rescue the fish from your own QT practice.
This is why it can make a tremendous amount of sense to put a new healthy-looking fish that eats well into healthy reef with other healthy fish.
At very least your QT should be a reasonable FOWLR setup for the size and number of fish you want to QT for observation. Bare glass, a little live rock and some fake plants is fine….even a little sand and some PVC parts are fine. The more seasoned it all is, the better.
A 40 Breeder or 50 Breeder can be just about ideal for QT, but go with the biggest you can accommodate and stock it LIGHTLY – I wouldn’t QT more than 1 or 2 fish at a time in a tank ≤20 gallons. I personally wouldn’t QT a fish bigger than a neon goby in a 10 Gallon. If you provide less than this, or you overcrowd what you do provide, you’re hampering your new fish and literally throwing in on the side of the pathogens.
Unfortunately, the typical maneuver when getting new fish these days is to cram anywhere from 5 to 10 new fish into a very small, newly setup 10 or 20 gallon bare glass tank outfitted with little more than a “seasoned” biofilter and some bare PVC parts.
The very smart, and almost universal recommendation to have a “live” ammonia monitor on these quarantine tanks means that these folks know it’s an inherently unstable system – easily “perturbed”, in the articles lingo.
You know the fish is already immuno-compromised from the stress of getting from the ocean to you, so if you QT your fish at home, this typical setup must not be the kind of QT you use for your fish in most cases.