Fish feed: Start all over again?

We still don’t know the requirement levels for some minerals and vitamins for farmed fish species. Do we have to start all over again? The changing requirement levels are mainly due to the fact that fish diets are changing rapidly from being marine based to plant based. In 1990, a typical salmon diet had no plant based oil or protein in it. This changed after 2000, when slowly more marine based ingredients were partially replaced by plant based ingredients. As of 2010, the percentage of plant