Quarantine Tank Deaths with Copper


New member
Hey everyone,

First time posting so I hope this is the right place.

Recently experienced an outbreak of ich or velvet (not sure which) in my 120 gallon mixed reef. Lost 5 fish over the course of about a month (2 Tangs, Blue-spot jawfish, royal gramma, and swiss guard basslet.)

Finally set up a 15 gallon quarantine tank on Dec. 9 2021, caught my 2 clownfish that were heavily infected, put them in the QT and started treating with copper (cupramine).

After following directions, the Copper levels were at 0.4 for about a week and the clowns were miraculously doing great! No more spots, eating again, swimming happily, etc.

Did a normal 20% water change on 12/15/2021. Did not add more copper.

Came downstairs to feed them this morning (12/17/2021) and both were dead at the bottom of QT. Copper tested at 0.21 (It had dropped).

Other levels tested:

Salinity: 1.028
Copper: .21 (HANNA)
Kh: 7.6 (HANNA)
pH: 8.15
Nitrate: 5-10
Phosphate: 0.1
Ammonia: <.15

Not sure what killed my fish. Possible that the ich or velvet got them? They were looking SO MUCH better and eating and everything for over a week after losing all the white dots.

Also, the display tank still has several fish in it, and they have not contracted the disease AT ALL. Still have 3 reef chromis, 2 watchman gobies, a possum wrasse, and a leopard wrasse; all of which are acting normal and eating all sorts of frozen food.

What the heck is going on?

Thanks for your input.



Active member
You need to run copper at the therapeutic level for at least 28 days to make sure you kill it off. I'm guessing it wasn't completely eradicated and when the copper level dropped it took out the fish.

You need to get all the fish out of your DT and let it go fishless for 82 days. (I believe that's the correct number of days, may be 72) Otherwise you will still have ich/velvet in the DT and you will continue to lose fish. Place the fish in QT and treat with Cu for 28 days.