Mycotoxins are secondary metabolites produced by filamentous fungi that could cause toxic responses when ingested by animals. The extent of production varies with geographic location, feed storage practices and processing methods. In the tropics, improper bagging, transport, storage and use of feeds with inferior quality of ingredients are ways in which mycotoxin is produced and is a great challenge that threatens life of culture fish. Mycotoxins in feeds are a problem of significant concern as farmers are taking steps to overcome the challenge of feed supply. The effects result in teratogenic, carcinogenic, oestrogenic or immune-suppressive effects, poor growth, low apparent digestibility, physiological disorders, histological change and death. The expression of mycotoxin impacts is influenced by factors such as age, nutrition, sex, species and the possibility of concurrent exposure to other toxins. The main target organ in animals is the liver; therefore, mycotoxin disease is primarily hepatic. Conditions increasing the likelihood of mycotoxin impacts in aquatic organisms include limited feed availability, environmental conditions that favour mould growth on feedstuffs, and lack of regulatory systems for aflatoxin monitoring and control. Mycotoxin's effect on these organisms is not only on health problems in exposed fish but also represents a high risk to consumers through residues in fish musculature. Therefore, control and prevention measures are needed to sustain the aquatic resources. However, several effective ways to prevent and control hazardous fungi and their dangerous mycotoxins have been presented.