I've always used copper (Cupramine) to quarantine for ich, treating for 30 days at the recommended concentration, and testing daily. Most of the time this seems to work, but lately I've had two QT tanks where, when I bring the copper back down and observe the fish before adding them to my DT, they re-develop ich.
So I've been reading all of
@Humblefish 's threads on ich, and I keep coming back to these two points:
- Theronts are the only stage affected by chemical treatments (ex. copper) and hyposalinity.
- The average time [for theronts to be released] is 7-14 days; however in at least one study (Colorni and Burgess 1997), it took 72 days for all the theronts to be released from a group of tomonts.
To me, this means that if we want to be 100% sure that the fish will be ich free, then any treatment has to last for AT LEAST 72 days to account for possible lingering encysted tomonts (and that's discounting anecdotal reports of ich infecting fish after longer than that, I saw one report that indicated a facility had QT'd fish in copper for 72 days and left the main tank fallow for 90 and ich still returned).
I wonder if there is an alternative. If I'm understanding the science correctly -- and that's a big if! -- I believe we should be able to do a
combination of copper and TTM to limit the treatment time. Here is my logic:
- Copper attacks the free swimming theronts. That means, at the right levels, copper *should* kill the theronts before they attach to the fish.
- A fish infected with ich is infected with the trophonts, which feed for 3-7 days before dropping off.
- Therefore, after ~7 days, a fish in copper should be free of trophonts, and no theronts should be reattaching.
- Therefore, if the fish is transferred after ~7 days from the tank with copper to a new tank that has just been set up (with known-clean water, equipment, etc), then fish should have no ich on it and should not be able to be reinfected.
- The old tank that had been running copper could be sanitized and allowed to dry to eliminate all possible encysted tomonts.
The primary flaw I see in this is, the copper may not kill
all of the theronts, in which case, the fish could be reinfected in the copper, and those trophonts could then be transported to the new tank. Another potential flaw is, while the average trophont may feed 3-7 days, are there reports of trophonts feeding for longer? I have not seen any studies.
I like the prospect of limiting my fishes' exposure to copper, but I haven't come across anyone ever talking about QT'ing for ich this way. Has anyone else tried this / heard of someone trying this? Any insight into whether copper will kill ALL theronts or just MOST? Do most people watch their fish in the same QT after treating with copper, or does anyone transfer to a new tank after standard treatment?
