Copper for only ~7-10 days?

[MellowReefer]

There's always a lot of discussion on whether copper is damaging long term to fish, and I don't want to stir the debate again, but I have an idea of how to shorten the exposure time and want to know what you think. Please tell me why this wouldn't work for preventing ich.

In theory, if you treated a fish in QT with copper (I use Cupramine) for at least 7 days (counting after you got up to the right dose) couldn't you move that fish into your DT knowing that it would not carry ich? Then leave the copper in the QT fishless for the rest of the time (4 weeks is what most people do).

Here's my reasoning: the theronts feed on the fish for about 3 to 7 days. Then they encyst on the hard surfaces in the tank. Then as long as there is copper in the tank they will die when they try to get back on the fish and won't even make it to the fish. So essentially after 7 days there should be no way for the ich to re-infect the fish as long as you have the right level of copper in the tank. Leaving the copper in the tank for 4 weeks or more is really about making the TANK free of ich. If you took out the fish after at least 7 days and then left the tank empty of fish for 3 weeks (or more) the tank would be free of ich too. The downside is you'd need to have an empty QT for that period (ghost feed to maintain biofilter).

Am I missing something? To summarize my plan: I would observe the fish for a few weeks and use Prazipro, then slowly ramp up the copper, then do 7 days of .4 copper, or 10 days just to be on the safe side, the move the fish to DT so it doesn't get more copper exposure than necessary, and leave the copper in the QT for another 3-4 weeks, then remove the copper for the next fish.

Of course if you put a fish in QT and you can see it has ich, you would probably want to do the full treatment time, so you can observe it afterward. Or transfer to a separate ich-free QT to observe and make sure it's gone.

 

[Mrscribbled]

All it takes is one detached cyst to some how make its way while catching the fish and moving to the dt.

 

[MellowReefer]

The experienced people on this site who use the tank transfer method seem to think the risk of that happening when catching a fish is pretty low. Reading many posts about tank transfer is what made me think of this.

 

[Deinonych]

Interesting theory. Why not just clean and sanitize the tank after you remove the fish? Part of the TT transfer process is sanitizing the tank and allowing it to dry for 24 hours. The parasites need water to survive, so drying it out ensures they are killed.

 

[MellowReefer]

Interesting theory. Why not just clean and sanitize the tank after you remove the fish? Part of the TT transfer process is sanitizing the tank and allowing it to dry for 24 hours. The parasites need water to survive, so drying it out ensures they are killed.

That would be an option. But I have a 30 gal QT that's been running for a while, and I would have to cycle it again. Guess I could seed some new biomedia in the sump. But it seems like a lot more work than just leaving it fishless for a while. If I was using a 10 gal QT I might do that.

 

[HumbleFish]

The theronts are the free swimming stage, which is most susceptible to copper treatment. The trophont is the "white dots" stage that feeds on the fish for 3-7 days. So, given the worst case scenario, it will take longer than 7 days to go from trophont to theront stage (as there is still a protomont to tomont stage in-between). Even more disturbing is this taken from one of snorvich's stickies:

The time required for theront development varies. In one study (Colorni and Burgess 1997), theronts emerged from a group of tomonts sometime between 3 and 72 days, with most released from 4 to 8 days after tomont formation. In another study (Diggles and Lester 1996c ), tomite development and theront release occurred, on average, between 5 and 12.1 days after tomont formation, depending upon strain and temperature. There was no correlation between tomont size and theront release.

As you can see, the life cycle of Crypto can be erratic and needs to be studied more in-depth. In the meantime, 30 days of copper treatment should suffice in most cases. However, even 30 days may not be long enough if you encounter an unusual strain, as the 1997 study did.

 

[MrTuskfish]

The big problem is that all of the ich life stages haven't read the rules. Theronts are supposed to feed for 3-7 days, I doubt if they all know this. This is really evident on the studies that show cysts still holding the next generation for up to 12 weeks. I sure wouldn't assume that all fish are ich-free after 7 days. I'm afraid there have been countless people who have tried to shorten the treatment time, using every method imaginable. None have worked, that I know of.

 

[Deinonych]

I will stick to TT or copper, myself.

 

[MellowReefer]

Tank transfer has the same assumption, that it won't feed on the fish longer than 7 days. But people seem to be having success with that.

In the end, I guess there's always a small risk that you will get a strain that doesn't follow the rules.

 

[HumbleFish]

Tank transfer has the same assumption, that it won't feed on the fish longer than 7 days. But people seem to be having success with that.

In the end, I guess there's always a small risk that you will get a strain that doesn't follow the rules.

Another thing to consider is that copper doesn't just zap theronts instantaneously. There's a "dying process". If just one manages to find a fish host, and transforms into a trophont before the copper can do it's damage; the cycle starts all over again. I suspect this happens a lot when copper concentration is too low. Treating for 30 days, while still not 100%, gives you a margin of error to work with. And it's still a good idea to observe for many weeks afterwards... just to be sure you got it.

 

[MadScientistWRX]

Another thing to consider is that copper doesn't just zap theronts instantaneously. There's a "dying process". If just one manages to find a fish host, and transforms into a trophont before the copper can do it's damage; the cycle starts all over again. I suspect this happens a lot when copper concentration is too low. Treating for 30 days, while still not 100%, gives you a margin of error to work with. And it's still a good idea to observe for many weeks afterwards... just to be sure you got it.

This.

I am on my 7th week and used copper for a month straight at the minimum recommendation at 2.5ppm.

Week 4-8 are copper-free with carbon running and water changes. The good thing about this process is that you can see if any white marks pop up again. If they don't pop up within the last month...I'd figure my fish are safe to go back in the DT.

This also allows the DT to kill off any parasites.

 

[MellowReefer]

Like I said, I'm only thinking of doing this for a new fish that I have observed for a few weeks and have seen no signs of ich. Definitely, if you know a fish has ich, you would want to be very conservative - like doing an extra tank transfer, extra week of copper, etc. And of course a few weeks after treatment to confirm. I'm just talking about new healthy fish from a good source that you don't suspect has ich.