Segragation Tank instead of Quarantine


Premium Member
We're having nothing but problems with a 20G standalone quarantine system.

We've now killed off more livestock in the quarantine that were in the original main tank. We're able to determine what happened each time and it always turns out to be a mistake caused by us. (Ammonia, lack of oxygen, stress etc.)

While a full QT is a best case scenario I'd appreciate comments on the following idea. I don't need comments about how important a QT is, I'd like to hear from people who use alternative methods.

We're going to plumb the QT into the main system. The rest of the tank has about 300G of moving water. Most of the water would run through the refugium and sump but a small amount would run into the QT and then back into the sump. I am thinking a very low flow 2x/ the QT per hour.

Everything would be running in the QT, heater, powerhead, filter etc. but the main tank water would be adjusting the fish to our parameters in a stress free environment. It would be easy for us to examine the new livestock every day and immediately upon noticing any problems we simply turn off the water flow from the main system. Everything for the standalone QT is already running so it immediately becomes a hospital tank. If we use any treatment we just sterilize it before the next use.

We always buy our fish from the same local LFS and never buy anything that hasn't already been in their tanks for at least 10-14 days already.



New member
By the time you notice a problem with the fish, it could have already infected your entire system. Its not a good idea at all to hook a QT tank to your main system.

Do you have this 20 gallon running all the time or do you only set it up when adding a new fish/coral? What type of filter do you have on it?


New member
whats the point of a quarantine if he's still part of the system ???

if anything; just do daily water changes out of the main system. but Id replace the water removed, not pump the water back in; otherwise you are accomplishing nothing other than limiting aggression to and from the new fish... which could be accomplished by just placing him behind some egg crate in a corner or something.


Active member
The point of the quarantine system is to keep parasites, etc. from entering the main system by allowing enough time to notice if the new fish is afflicted with anything, and if it is, then treating it. If you wanted to tie the QT to the main system, the only way I would recommend doing so is to use a UV sterilizer on the water coming from the QT and entering the main system. This will prevent contamination of the main tank, but it will not allow you to medicate the QT tank if necessary. You will then need to take the QT offline and medicate.
Hope this helps.


Premium Member
The point of the segregation is to allow the fish to adjust to my water parameters in seclusion with minimal stress.

I tend to follow the concept the parasite is in the water and it's stress that lowers the immune system of the new fish to allow it to manifest into a problem.

I had considered running the water from the QT into a UV before it enters the main system again but there are some good arguments as to the value of UV.


Team RC member
Team RC
Well clearly you have already made up your mind and are simply looking for someone, anyone, to confirm your viewpoint. I run a quarantine tank all the time so it is already available for new inhabitants. Anything which shares water does not quarantine. If you are simply looking for social acclimation, get a hang on breeder that isolates the new fish.


New member
Im curious though to find out why you have problems with ammonia. What are you doing to the filter to prepare it for a QT? If this tank is setup right before you add a fish then that is your problem.

If you are using some sort of power filter like a Penguin then you should hook it up to your main system for about 2 weeks before purchasing anything. That way it will build up the benficial bacteria thats needed so you wont have to worry about any ammonia problems. As soon as you transfer the filter over to your QT, it will have everything needed so you wont get any spikes.

While its true that diseases like Ich can be already in your system and stress can bring it out, there are plenty of diseases that no matter how you introduce your fish, it will still be sick. That disease can then transfer to your main system if hooked up inline.

Dont trust your LFS to properly quarantine your fish. Just because youve had luck so far, doesnt mean nothing will ever happen. 10-14 days is nothing and you never know what they have in their system.

I dont want to generalize but most LFS's dont give a damn about you or your tank. Most also dont know what they are doing. Finding a LFS that isnt still stuck in the 1980's are few and far between.


Premium Member
Thanks for all the constructive feedback. We've decided to go with a standalone quarantine again rather than plumb the system inline.