Aquaculture is critical for ensuring global food and nutrition security, and fed-aquaculture, which depends on formulated nutritionally balanced manufactured feeds, must be sustainable. Single-cell ingredients (SCI) are predicted to play a significant role in future aquafeeds and have the potential to underpin sustainable fed-aquaculture for many species. The value of an aquafeed ingredient includes nutritional, commercial, environmental, and socioeconomic factors. Here we aim to review approaches to understanding the value of ingredients and use this to outline a practical approach for considering the use of SCI in aquafeeds. We conclude that following an initial experimental focus on nutritional value, a collaborative and iterative approach with an aquafeed manufacturer will provide the most likely route to successful commercialisation of SCI.