No way to tell from a dead fish.
I would strongly advising against copper, especially if you don't know what you have in your tank. Copper may just make matters worse by diminishing the fish's immune systems.
Also copper is only effective at the right dose, which has to be maintained precisely throughout the treatment. This dose may also be different for different parasites.
Copper in a DT with coral sand and calcium containing rocks is bound to fail and the copper bound by sand and rocks will later cause a lot of negative long term effects.
When in doubt, TTM in combination with at least 1 or 2 formalin dips is a good "catch it all" treatment against protozoan parasites.
You can also add CP if velvet is of special concern.
PraziPro can be added if you are concerned about worms or flukes
I also read TTM would not work with Velvet.
Neither does hyposalinity.
And copper is questionable in it's affectivity as well.
Only sure thing against velvet are formalin and CP
I would also not trust cupramine or copper in any other form to be reliable against velvet (or even ich)
Chloroquine Phosphate (=CP), if done right, kills both.
New Life Spectrum Ick-Shield Powder is CP and you get it at Amazon without the need for a prescription.
But TTM would not be feasible, I am doing the Hyposalinity method.
I had the temp down to 69F to reduce swelling and easier for the sick fish to breath. My Copper is only 0.1- 0.2, Salinity is 1.015.
Goal:
Salinity to 1.009 by Friday 1/22
Temp to 76F by Friday 1/22
Raise to 86 by next 1/27, speed up the ich cycle (what about the m.velvet?)
Change water as needed.
Will adjust DT salinity to 1.015, is this reef friendly?
This treatment to 2 month
At 3rd month, prep to inbound back to DT with salinity at 1.015, temp back to normal 76F
Please advise if this ok. Thank you.
I strongly recommend to stop messing with the water temp. Moving between 76->69->86 is only going to stress and help kill the fish.
-Matt
69F is too low for tropical fish. 72F would be the bare minimum, 74F is the low end of the ideal range.