QT water changes


New member
I have had my first fish in quarantine for a week now. I'm wondering how often most people need to do water changes during quarantine? I have one fish in 12 gallons of water (partially full 20 gallon tank) and have to change about 50% of the water every 2-3 days because the ammonia gets to about .50ppm in that time. Is this normal? Or is it because I don't have a sponge with a good load of healthy bacteria? Thanks!



Obligate Feeder Obsessed
If the ammonia is getting that high in would recommend doing more frequent water changes. You don't want any detectable ammonia in the water.

My qt is cycled. Using a sponge I seeded from my DT a while back. As such I change the at water once a week with the old water from my DT change.

.5 PPM is a lot of ammonia. Do you have any seeded media from your main tank you could use? What about getting a bacteria seeding product like sea hem stability, or an ammonia binder like amquel coupled with daily water changes?

Any amount okf ammonia is harmful to your fish, but that much could prove fatal quickly.


Team RC
+1 to the comments above. Are you using any meds? If so you shouldn't combine with prime or any other water treatments. It's best to have the QT cycled ahead of time, but if you didn't I would keep up the water changes.


New member
No meds so far. Since I'm not dosing meds, could I add some live rock rubble from my display tank setup into the filter to hopefully seed the sponge? I would not put the rock back in my main system and would take it out of the filter if I need to give any meds. I did 20% yesterday and 20% today and ammonia is down to .25ppm. Will do a 50% water change tomorrow.


Team RC
Why not use the whole tank's volume? With only 12 gals in a 20 gal tank, your ammonia level is 40% higher than it needs to be.


Premium Member
I also quarantine in a 12 gallon tank and I change one gallon of water daily, using water from the display and discarding the old QT water. When I siphon the QT water out, I vacuum up any detritus from the bottom and that seems to keep the ammonia at bay. An added benefit is that when it's time for your fish to go to the display tank, the water in each is identical. And, by all means, fill your QT up because more volume means less ammonia.


New member
Only kept the level down because I have no lid for it. Didn't want to find the fish trying to swim on my tile floor. :)