I don't really think that Oscars are sensitive to water conditions. They can however be sensitive in an emotional way. My Oscar tends to act like a 15 year old girl with cramps. If I walk by the tank without feeding him, he pouts. Change anything in the tank, he pouts. Vacuum the gravel, he pouts. Usually by going to the corner and lying on his side.Question: how can Oscars be so sensitive sense i seen them living in local polluted fresh water canals?