Copper Treatment on Red Stripped Cardinalfish

[danjp]

I recently began a copper treatment in a quarantine tank for 3 red stripped cardinalfish and 2 neon gobys I recently acquired. I had issues with marine ick in the past from fish purchased from our only LFS so I am doing this as a precaution. (Don't want to rip down my main display tank again)
I slowly acclimated the fish into my quarantine tank (bare tank) and then waited two days before starting the treatment so that they had a chance to adjust and I could make sure they were eating OK and did not have any other issues. I also test the water parameters prior to adding the copper and ammonia, nitrite, and nitrate where all 0, PH was at 8.4.
Since I am aware that fish like gobys can be sensitive to a copper treatment I started with 1/2 of the recommended amount (Cupramine: 1/2ml per 10.5 gal instead of 1ml per 10.5 gal recommended) for the first day. The quarantine tank is 30 gallons so I added 1.5ml. I was going to add the other half dose after 48hrs and then again to achieve a final concentration of 0.3-0.4 mg/l, slightly under the recommended 0.5 mg/l. Within 24 hours all 3 of the red stripped cardinalfish were dead. The gobys seem fine. I had tested the water after a couple of hours after adding the initial copper dose and it was at ~0.1 mg/l which is where it should have been at. I am using the Salifert copper test kit. After I discovered that the fish died, I immediately tested for ammonia, nitrite, nitrate and PH. Ammonia: 0, nitrite: 0, nitrate: 0, PH 8.4, temp 77F. Right now I am at a loss as to what may have gone wrong. So I would like to know if the cardinalfish are very sensitive to copper or if anyone else has had a similar experience. Thanks.

[leebca]

Sorry for your loss.

The Cardinal Fish is one of the few fishes I've never treated for Marine Ich. I have not heard or read where they can't be treated with copper, however Cupramine is about as gentle a copper medication as you'll find. Still, I would have followed directions the manufacturer has provided.

Like I've always said and written, do no treatment to new fish unless they are infected with a (reasonably) known problem. I only have two exceptions to this guideline.

[danjp]

Sorry for your loss.

The Cardinal Fish is one of the few fishes I've never treated for Marine Ich. I have not heard or read where they can't be treated with copper, however Cupramine is about as gentle a copper medication as you'll find. Still, I would have followed directions the manufacturer has provided.

Like I've always said and written, do no treatment to new fish unless they are infected with a (reasonably) known problem. I only have two exceptions to this guideline.

Thanks for your reply. I agree that Cupramine is the best. I have used it in the past without incident. I also agree with you that do not treat unless necessary but our LFS does not quarantine or treat any of the fish they get and I know from experience that their fish tend to have ick but are otherwise in pretty good shape. That was why I chose to do the treatment.

As an update I also lost both gobys.

But the one thing that I did not indicate in my first post (as I did not consider it an issue at the time) and I believe may have actually caused the problem is that this was a tank I just re-sealed, unlike when I used it before in a different tank. I used GE Silicone II glass (100% pure silicone - clear). I did let it dry for several weeks before using it so I dont think that was the issue but, upon a closer read on the tube I noticed that it contains a mold inhibitor. I should note that this is not obvious and was only something I discovered after re-reading the tube several times and was clued into after looking for a possible answer to my initial problem. I have re-sealed numerous tanks over the years and always used GE clear silicone without incident but it seems that all the new GE silicones have this inhibitor which before they never had.

So I think what happened was when I removed the carbon and added the Cupramine, there was a reaction with the inhibitor that caused the water to turn poisonous. Either from a reaction of the inhibitor and Cupramine or directly from the inhibitor. I do not have a way to know for sure so I can only assume. What I do know is that the level of copper I introduced should have by itself not caused an issue. I also think the reason that everything was OK for the first few days was due to having carbon in the filter. It was probably absorbing anything that was being leached.

So I am removing all the sealer and am going to replace it with an aquarium safe silicone. So I would advise anyone who may be doing a reseal to not use anything but a guaranteed aquarium safe sealer as it seems that all the new formulas are coming with a mold inhibitor. While I see that there is a lot of controversy in the various groups about using this product (some say OK other against) I can only pass on my experience with it which if was truly the cause, was not good.

Again, thanks for the reply and I hope that this may help others.