This article critiques the "Fish In, Fish Out" metric commonly used to evaluate the sustainability of fishmeal and fish oil in aquaculture diets, arguing that it fails to adequately measure sustainability or efficiency and ignores the human health aspects related to fish farming. It points out that the metric does not account for the value-added factor of long-chain omega-3 content, which is crucial for human health but is lower in fish raised on diets lacking marine ingredients. The authors advocate for the continued use of fishmeal and fish oil from sustainable fisheries due to their ecological efficiency and emphasize the importance of well-managed fish harvests for global health.