Morning, half the loaches are dead. I think at this point I'll just treat with meds the tank with the intent of protecting the other fish.Loaches usually don't handle meds very well. IMO, the heat treatment is the best option.
Bump the heat up to 86 - 87 degrees for the next 10 days. Do a 10% - 15% WC every other day, making sure to thoroughly gravel vac.
Make sure to provide plenty of flow & aeration.
Hope they heal up quick.