My gas water heater pipes have corrosion at the copper to galvanized metal connection. Can it be fixed, and if so with what and how?
Are you sure that’s galvanized? Everything else (I know it dirty and hard to see) looks like black pipe. Which makes sense. But galvanized and gas is a huge no no. If it’s a water pipe, then turn off water heater and everything else and unthread that piece of pipe and get a new piece from a home improvement store.