Feed is one of the important factors in aquaculture with a high enough content value for fish. So the need to formulate high-quality fish feed that suits the needs of fish increases. Lemna sp. is a water weed that can be used as an alternative ingredient for fish feed. This is because Lemna sp. has a high content of nutrients. A high crude fibre content in vegetable ingredients causes one of the obstacles to use as fish feed ingredients. However, this can be overcome by processing feed ingredients using the fermentation method. With the help of fermenter solutions, the fermentation process can produce simple combinations. This makes it easier to decompose than before. The fermentation procedure can affect the nutrient content of nutrients in Lemna sp. with flour and molasses and probiotics during the three-day incubation period is the best fermentation procedure. Fermentation is influenced by several factors, including the duration of incubation, number of inoculums, dose of probiotics, particle size, and pH.

This article aims to review the potential of fish scale waste as a processed material and its application to various fields of the non-food industry. The method used in this process is a qualitative descriptive method using data collected from secondary sources. Fish scales are residual waste that can be obtained from waste created in fish sales or fish processing companies. This type of waste has the potential to be utilized because it contains various kinds of organic materials that can be reprocessed to become new products. Fish scales waste can be used directly into handicraft products, including brooches, beading (sequins) and used indirectly in the form of products from collagen extraction, including fish glue and products from chitosan fish scales, including bioplastics, biocoagulants, and Rhodamin B dye adsorbents. The importance of utilizing fish scale waste is that it can increase the selling value of fish scales which were once just waste into potentially useful materials, reduce environmental pollution, encourage the concept of a green economy, and create a zero waste environment in the fishery product industry. From the data that has been collected, it can be concluded that fish scale waste can be used in various non-food industries and can be processed into various products, this includes the use of fish scales as craft products such as brooches or key chains, processing fish scales into adhesives, and extraction of chitin from fish scales to be used as additives for bioplastics, biocoagulants, and rhodamine b adsorbents.