Black soldier flies can help with many different things, but they cannot do everything. One thing that they apparently cannot do is replace fish meal in the diet of pearl grouper.

Huang, B., Zhang, Y., Zhang, S., Dong, X., Chi, S., Yang, Q., Liu, H., Deng, J., Tan, B. and Xie, S., 2023. Dietary application of Hermetia illucens larvae meal negatively affected the fillet quality and fatty acid metabolism of pearl gentian grouper. Journal of Insects as Food and Feed, https://doi.org/10.1163/23524588-20230007

Black soldier fly (Hermetia illucens) (BSF) is an insect that can be fed with food waste, and its larval meal is now studied as a feed ingredient to reduce the use of fish meal. However, adding BSF into the feed of pearl gentian grouper (Epinephelus fuscoguttatus string♀ × Epinephelus lanceolatus string♂) did not give good results. Higher levels of BSF substitution caused disorders of fatty acid metabolism, leads to fatty liver, and caused oxidative damage in the liver. Also, higher levels of BSF substitution reduced percentage of thick myofibers and significantly affected 40 of metabolites, including dodecanoic acid, D-lyxose, D-aspartic acid, and glutathione in the muscle, which did no positive effect on the improvement of fish meat. Therefore, BSF may require further processing, such as degreasing, in order to be better used.