More production is needed as fish consumption increases. The increasing demand for fish also has implications for fish feed, the efficiency of its production and sustainability. Three protein alternatives – Black Soldier Fly, Yellow Mealworm, and Soybean – are compared to assess the sustainability of raw materials and their environmental impact. Each alternative has advantages and disadvantages. The advantages of Black Soldier fly and Yellow Mealworm are a valuable source of protein, sustainable growth (as the feed can be used in food waste) and no need for arable land. The disadvantages of Black Soldier fly and Yellow Mealworm are cost, unbalanced diets can adversely affect growth, and the nutritional impact on fish varies depending on the species of fly or mealworm. The advantages of soybeans are price, availability, and high protein content, while the disadvantages are the lack of essential amino acids, which affect the quality of the fish, and poor taste. An LCA study has been carried out on the proteins of black soldier fly, yellow mealworm and soybean. The most important impact categories from the PEFCR are climate change, particulate matter, acidification, land use, terrestrial eutrophication, and water use. The total single point value for the Black Soldier fly protein is 1.43E+01 µPt, the Yellow mealworm protein is 3.89E+02 µPt and the Soybean protein is 9.72E+01 µPt. The significant effect is due to the electricity consumption and the ingredients used in the feed. Sensitivity analysis was carried out for Black Soldier fly protein and Yellow Mealworm protein production where feed formulation was varied. In both sensitivity analyses, the lower environmental impact is from the new feed structure, which may be due to the use of food waste and wheat as feed ingredients in the new feed structure.