Hot Tips: Quarantine Tips

by | Apr 15, 2004 | Advanced Aquarist | 0 comments

A selection of useful tidbits of information for the aquarist. Readers are encouraged to send their tips to [email protected] or to post them to our Hot Tips sticky in the Reefs.org General Reefkeeping Discussion forum for possible publication. Next month’s Hot Tip theme will be “Critter Selection Tips“.

Quarantine Tips

I always cover the sides of my quarentine tanks with dark, non-reflective fabric. A lot of wholesalers use this practice on transhipped fish. I also open the bag (or box if it’s shipped livestock) in dim lighting. Both measures are employed to reduce stress of newly introduced fish.

— Len


Make sure that the q-tank is sufficiently large that the occupant in not stressed by the size of the tank. In cramped conditions, the quarantine process could do more harm than good.

— Jeff CC


You should quarantine both inverts and fish, if only to reduce the number of simultaneous stresses on any new critter. Inverts carry parasites as well and you should use the time in quarantine to carefully examine the new arrivals and if possible give them time to recover with as little stress as possible. Also, if you happened to purchase a soft coral or other invert that appeared healthy but was actually quite sick, you don’t put your whole tank at risk of a crash if it dies. Even new live rock should be quarantined for unwelcome hitchhikers, though simple base rock obviously doesn’t need as much care as an uncured rock with a lot of varied life, for instance.

You should have a separate tank for invert quarantine from your regular fish quarantine tank (so that any copper/treatment residues on the aquarium and filter components don’t leach back into the water and kill your inverts for you). I painted the front and sides of the fish quarantine tank with a red “Hospital Tank”, “Fish Only”, “Medicines-OK” messages and a big Red Cross (+) medical symbol to make sure that there’s no confusion from family members and friends when quarantine coincides with a business trip or vacation and I have to trust someone else with treating my fish.

In the fish quarantine tank, try to limit your decorations to PVC (so that they won’t absorb much of the various treatments you may need to use), but still try to create shapes that the new fish will find comforting (8″ long 8″ diameter PVC with one endcap for a Gramma or other cave dweller, 20″ long 1″ PVC tube with both ends open for a Watchman Goby, at least one good pile of mixed pieces for Chromis, etc.). I like to have a collection of PVC lying around so I can usually scrape something together appropriate for any new arrival.

For my fish quarantine tank, I selected a standard 29 gallon tank to get some length without too much space being taken up and without spending a lot of money. I also bought a wooden stand that can hold two tanks. When running, the tank is on top of the stand with support materials underneath. When not running, the tank and pile of equipment are inside the stand taking up a lot less space while packed away in storage.

My invert quarantine tank is actually a 20 gallon invert only nano-reef that I leave set up all the time. By leaving the invert quarantine tank as a running nano tank, it just looks like a second aquarium in the house and isn’t nearly as much of an eyesore as the sparsely populated quarantine tank which is only set up when needed (and in an out of the way place).

If I detect a nasty parasite (like a tiny little Millepora-eating nudibranch that I caught in there) then the quarantine tank really begins to earn it’s keep. At that point, I’ll attempt to do what I can to “cure” the infected invert. If I fail, I’ll do my best to be sure that the quarantine tank is free of the parasite (if the bug can only survive on Millepora, then when the Millepora has been gone for three months, I’ll feel fairly safe putting another coral frag in there). If I can’t be sure that the tank is free of the parasite, I’ll scorch the invert quarantine tank and start it over.

Use the water you take from main tank during a water change for the quarantine tanks, or if that’s not practical, mix the water for the quarantine tanks exactly the same way you mix for a water change in your regular tank.

If you don’t have a fish quarantine tank that you keep running all the time (some people keep a tank with a few tough fish for just this purpose), you’ll need to jump start the bacterial populations, especially with more sensitive new arrivals. I like to take a filter sponge and leave it in my sump for three or four days before the new arrival shows up. The night before the purchase, I’ll fill the quarantine tank with tank water and the next day I’ll move the sponge to the quarantine tank’s filter while dripping tank water into the transfer bag.

Some people recommend adding copper to the quarantine tank in reduced dosages to discourage any parasites that may not be visible. I don’t know for a fact but I suspect that this practice may eventually produce copper-resistant parasite strains that we will all have nightmares with down the road. If you’re going to use copper, I suggest making sure the fish has an infection that will be helped by copper, that the fish can deal with the copper, then using the full recommended dose for the full amount of time.

If the fish in your tank have a parasite infection, don’t screw around with garlic and other ineffective herbal remedies: clear all of the fish to the quarantine tank, treat the quarantine tank with the medications that work, and keep the fish in the hospital tank until the disease is absolutely gone. Taking the fish from the main tank sounds like a lot of trouble (it can be), but the only treatments of marine velvet and ich that are known to actually work can only be done in a true fish only tank.

If you religiously quarantine all fish coming into your tank, you will never have to deal with moving all of your fish from your main tank to the quarantine tank and treating them for some disease. The disease will never have a chance of entering your tank. To me, this is the best possible reason to go through the trouble of a quarantine tank in the first place.

— Ross, aka “rabagley”


In some cases, we are limited by space and budget and can only have one QT tank. If this sounds like you, make sure the filter system you use has some type of skimmer that will allow you to keep fish or more delicate inverts and corals for the observation period. Just make sure it operates on it’s own so you can disconnect or turn it off when necessary. A QT tank doesn’t do much good if your new arrivals get further stressed or don’t make it out due to improper water quality.

— J. Howard


Ross has chanted my mantra, including q/t of inverts, so there’s not a whole lot I can add to that. I have a feeling he’s handled very large numbers of fish and inverts, or has learned from someone who has – it always pays to quarantine. Would a public aquarium, upon acquisition of new specimens, just drop them into their displays? Absolutely not, there is a very specific protocol for all new arrivals, and it includes a minimum of 30 days disease/trouble free. And there is a very good reason for this: if it gets loose among the population the results can be catastrophic in a manner that far exceeds anything the home hobbyist need consider. “Down” displays are displays that can’t make that aquarium/zoo money, not to mention it’s quite expensive to treat and/or restock.

However, folks don’t realize that a fish (or invert) can be kept in anything that holds water and is chemically inert. This is why, for those who, for whatever reasons can’t set up another actual aquarium, I recommend Rubbermaid tubs – stackable, 30 gallons, sturdy, chemically inert, inexpensive. Also, speaking to PVC use, Steven Pro had linked me an article once that seemed to demonstrate a marked difference in recurrence of ich (the bane of all fishkeeping, honestly) with fish kept in systems with porous materials (i.e. live rock) and systems with non-porous materials (i.e. PVC). Guess which system experienced more trouble with recurrences and needed repeated treatments.

Also, at this point I think it’s a good idea to mention that there can be a difference between a hospital tank and a quarantine tank. Quarantine only means to keep separate from, whereas hospital speaks directly to the need for treatment. That being said, I have learned (through my years working the trade – both retail and wholesale), and subsequently prefer, to use only those items that can be easily sterilized in quarantine. This need precludes things such as macro algae, live rock, et al.

I’d like to mention the use of hyposalinity and freshwater dips. Many folks feel it’s too stressful, but I disagree. I feel it’s a technique whose efficacy has been well-proven when treating things such as velvet and black spot disease (which can be eliminated through dipping and hypo alone). I feel this is a good tool well-used, have always done this with good results, and advocate it. The only (very few, less than a dozen, in relation to handling thousands of fish) times I’ve lost fish to dipping was when they were extremely ill in the first place. I made it part of my standard regimen pre- quarantine introduction routine and pre-display introduction – along with making sure the water’s matched for temperature and pH, I like to add enough methylene blue to turn the water a rich blue.

— Seamaiden


I keep a simple sponge filter (large breeder size) at all times in the sump of my main tank for emergency use for either a Q tank or Hospital tank. Makes it easy to set one up in a hurry.

— Lawdawg

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