No extreme measures for me. When I see anything causing injury to any of my fish, my first response is always a huge water change, just in case something is wrong with the water.
We only measure nitrogen with our test kits but lots of other chemicals exist in typical tap water and aquarium water. Since I can't measure them, I simply assume there may be something wrong and start by providing known good water for my fish. In almost all cases, the fish start to improve almost immediately.