Some of the commonly used ingredients in fish feed are made up of grains and their by-products, which constitute a natural substrate for fungal development that may lead to mycotoxin synthesis. According to the authors, the actual acceptance levels of mycotoxins suggested by the FDA, EC, the Codex Alimentarius or the ESFA in ingredients cannot ensure harmless effect of mycotoxins in fish feed. Indeed, fish feed samples revealed significant levels of mycotoxins in several studies, with most often a polycontamination. Moreover, many studies have been done to determine the mycotoxins symptoms in fish under various conditions. Though the toxic effects in animals vary according to the type, amount, and period of exposure, mycotoxins were shown to cause reduced growth, reduced survival, immune suppression and morphological changes in fish. Thus, losses in aquaculture caused by mycotoxins in feed can be significant, resulting in economic losses in fish production. To go further, mycotoxins in fish feeds are a risk for human health, as they can be stored in fish muscles and liver and therefore be consumed by humans. In this respect, authors stress that the presence of residues in fish tissues or organs should be better regulated and highlight the need to assess safe levels of each type of mycotoxins in the different tissues for several species of fish. Authors also remind that the reduction of the mycotoxin risk starts upstream with proper field and storage management. Moreover, they mention that the use of feed additives for the reduction of the contamination of feed by mycotoxins may provide new opportunities for managing mycotoxins problems in aquaculture.