Aquaculture is the development of aquatic organisms under controlled or semi-controlled conditions, thus being one of the best economic options for obtaining animal protein. The last decade has seen a development in aquaculture worldwide, although focusing on developing countries, because it has the potential to produce more fish at lower cost, covering the demand that will be presented by the population explosion without affecting the ecology and producing safe, high quality food with an excellent nutritional profile. In the present study, several experiments were carried out to evaluate the effect of fermented apple bagasse and the use of a yeast-based additive in the diet of tilapia fish (Oreochromis niloticus) during the growth stage. Both the fermented bagasse and the yeast additive were prepared by aerobic fermentation processes.