Minimum quarantine length?


New member
Hello Andrew,

Thank you for your informative article. I very much enjoyed it and have greatly appreciated your new magazine thus far.

I have a question about quarantine lengths. In your article, you support a length of 4 weeks and present arguments supporting a 6 week stay when possible.

I had been under the impression that two weeks was usually enough, what with two weeks being a complete marine ich lifecycle.

You understand of course the attractiveness of cutting short the quarantine period. Could you please comment on the additional risks being taken by the hobbyist when the period is cut down to three weeks? And to two? Although the last thing I want to do is put my fish at risk, my successful experiences thus far make me reluctant to move to four without a good understanding of the difference in likely success or failure.

Thank you most kindly,

It is my understanding that the life cycle of Cryptocaryon will vary with temperature bewteen around 2-3 weeks. At normal reef temperatures (80-84°F) it is probably closer to 2 weeks. The main problem with "Ich" infections is they tend to get worse with each cycle. So what may start as a few spots may be somewhat thicker 2 weeks later and a complete covering 2 weeks after that.

The danger is if the first infection with the parasite is so mild that you miss it and you only quarantine for 2 weeks, the fish will be in the main tank before it shows again. Leaving the fish in the quarantine tank for 4 weeks increases the chances of seeing the "Ich" because it will include at least 1 complete cycle. Going for 6 weeks means at least 2 complete cycles and if in that time there is no sign of "Ich", you can be confident that it is unlikely to appear.

As far as leaving them in the quarantine tank longer there should be no problems. I regularly leave my fish in my quarantine tank for long periods without bad effects. The fish I currently have in my q tank have been there more than 6 months. I had planned to move them to one of my reef tanks and they would have been moved 4 months ago, but I changed my mind and am instead setting up a new tank for them. These fish are doing fine, eating well and growing quickly. Of course, it means I can't get any new fish, but as I catch most of my fish and the season doesn't start for another few weeks, that has not been a problem.

I hope this helps,

Hello Andrew
Could you please explain the process of "hyposalinity treatment" in your article, that you have used wiith success. Is it suitable for treat in every state of Ich lifecycle?

Waiting for your answer,
Thank you.
Tommy N.
You mean to say that there is no propblem to leave the fish in a quarantine tank with a hyposalinity water ( salinity 1.011) for 4 weeks?
<a href=showthread.php?s=&postid=7663788#post7663788 target=_blank>Originally posted</a> by baruchbl
You mean to say that there is no propblem to leave the fish in a quarantine tank with a hyposalinity water ( salinity 1.011) for 4 weeks?
I'm not sure to whom this question is directed.

I (and may others) have had great success in treating Cryptocaryon using hyposalinity. This is where the specific gravity is lowered to 1.009 (salinity between 12 and 14‰ ) and left there for at least 4 weeks - duration of life cycle. This has little or no adverse affect on the fish - in fact many studies have shown that most bony can survive at the specific gravity indefinitely and some even do better.