You can use certain coppers with puffers and sensative fish. You just can't go fast with it. You have to acclimate them slowly to it. I used cupramine with my porcupine puffer at 0.35-.0.40 ppm. I did 1 drop per gallon every other day until I got to 0.35-0.40 ppm. I held it there for 4 weeks. I had to do water changes and add cupramine to the fresh salt water as well keeping in mind the drops per gallon used in the qt and retest the qt water to ensure the dosage was not exceeded. I'm not sure how sensative dogface puffers are, but you could try 1 drop per 2 gallons every other day. Do not do hypo and copper at the same time. You may have to bring up the salinity slowly in order to do the copper treatment. I did buy some Chloroquine Phosphate to have on hand for any future fish to try, but have never used it yet since the copper did the trick with the fish I currently have.