Should I be eating more fish during pregnancy?

Not necessarily. You should have a well balanced diet - that may include fish. You should limit your consumption of large saltwater fish to one serving per week to minimize mercury intake.
Yes. I think the fear of fish is totally unfounded. The healthiest people in the world eat fish. The benefits of dha on fetal development were observed in pregnant women who ate fish. There has never been a case of mercury poisoning in humans from too much fish consumption.