I've got a couple of dwarf gouramis, one of which is looking decidedly poorly, and I reckon its got dwarf gourami disease. Is there anything to be done for the other one , and to protect the other varieties of gourami sharing the tank?
Treat for what exactly ?Take the sick grouami out, put it in a separate tank/plastic box with an air stone and a heater. Monitor it and other fish, feed high protein food. You could medicate the lone gourami and the tank if you see any signs of sickness.
To be honest I think the Aquarium Coop QT trio is a scam. A dewormer okay, but treating with meds as precaution I think is ridiculous. The mis- and overuse of meds is one of the biggest issues in our hobby.There is some medicine specifically for quarantining new fish. Aquarium Co-op goes in depth about quarantine and medication. You might want to check it out. You usually treat for ich, bacterial infection and deworming the fish.