Aquaculture farming discharges large volumes of fish sludge, consisting of particulate organic matter from feed spill and feces. Fish sludge from land‐based salmonid aquaculture systems can potentially be used to feed low‐trophic species such as marine polychaetes and insects. Further use of these invertebrates as feed may provide a more sustainable feed chain. However, food security must not compromise feed or food safety. Th...