The by-products from processing plants are rich in nutrients and they can be further manufactured into an alternative feedstuff. Fermentation of these by-products increases the degree of protein and lipid hydrolysis, and the production of antioxidant compounds. This technological approach to treat this resource is safe, environmentally friendly, and it has a low-energy demand. This study explored the utilization of the fermented silage on catfish by-products (viscera, head, and frames, as well as the whole by-product). The catfish by-products were frozen, ground, and homogenized. They were further subjected to incremental levels of Lactobacillus plantarum (ATCC14917) at 2.5, 5.0, and 10% w/v, and three inclusion levels of carbohydrate (5, 10, and 15% w/v of corn syrup). The samples were incubated at 30°C for 7 days, and temperature and pH of the samples were monitored daily. After the incubation period, the resulting samples were subjected to proximate composition, foaming capacity, emulsifying capacity, and protein solubility. The pH presented a steady decrease until the third day of ensiling and remained stable until the seventh day. This result was consistent for all the other treatments, except for the silages with a 5% carbohydrate inclusion, in which pH was stable and samples spoiled, likely due to the insufficient carbohydrate nitrogen ratio, which his necessary for the proliferation of lactic acid bacteria. The proximate composition varied among the silage manufactured, reflecting the characteristics of the nutrients from the original by-products. The silages had an average dry matter content of ~38%, and the protein and lipid content were similar for silage made from All waste and frames, with an average of 36% crude protein and 34% lipids. The mineral content was lower for silage made from viscera (1.5%), but it had a higher lipid content (60%). The emulsification properties of catfish silage varied across different treatments, in which the whole by-product displayed a superior emulsification stability when incubated with a 10% bacterial inoculum and 10% carbohydrate inclusions. There was little variation in foaming stability in catfish silage, except when considering the interaction between silage and the levels of bacterial inoculum employed. The soluble protein varied between the source of by-product, with the viscera silage showing the highest soluble protein content (3.3 mg/mL). Fermented silage performed best with a 5% inclusion of lactic acid bacteria and a 10% carbohydrate source.