Mycotoxins in Fish Aquaculture—Occurrence and Future Perspective

Mycotoxins are toxic secondary metabolites produced by filamentous fungi which are commonly found as natural contaminants in food and feed worldwide. In recent years, aquaculture research has increasingly focused on changing fish feed by replacing traditional protein sources with plant-based and insect ingredients to promote sustainability. However, this shift has raised concerns about mycotoxin contamination in farmed fish, fish products, and processing by-products. As a result, the pursuit of sustainable aquaculture practices may inadvertently increase the risk of mycotoxin exposure. To date, studies on freshwater fish have focused primarily on regulated mycotoxins, and the findings have demonstrated their occurrence in muscle, liver, intestine, ovaries, and hepatopancreas. Most studies have investigated aflatoxin B1, and its presence has been confirmed in the muscle tissue of several fish species. In marine fish, research has encompassed a broader spectrum of mycotoxins, including emerging and masked forms, across multiple tissues and organs. However, across various studies, conflicting results have been reported regarding the occurrence of emerging mycotoxins, particularly enniatins and beauvericin. This paper reviews current research on mycotoxin contamination in farmed fish, summarising detected levels across freshwater and marine species and in derived products, and also discusses future perspectives on mycotoxin risks in sustainable aquaculture.