In the last years, the profitability and sustainability of the aquaculture sector has been addressed, with strong efforts being made to replace ingredients from animal sources (fish meals and oils) traditionally used in aquafeeds, by vegetable sources (e.g., cereals). However, this strategy may raise negative implications, as cereals (e.g., corn, wheat) commonly used in aquafeeds often contain high levels of toxic metabolites produced by fungi, i.e., mycotoxins. Consequently, a higher incidence of mycotoxicosis in fish is expected to occur, which can ultimately cause adverse health effects in animals and humans. Little is known about the effects of ingestion of contaminated feeds with mycotoxins by fish, as well as the effects on their gastrointestinal tract (GIT) and absorption efficiency in the gut, thus remaining a serious food safety concern.