Fish like other animals have a requirement for essential nutrients in order to grow properly. In the wild, natural feeds are available and as the fish forage for there, they are able to meet their needs. When fish is removed from its natural environment to an artificial one, enough food must be supplied in order to enable them grow. Artificial diet may be either complete or supplemental. Complete diet supply with all the ingredients (protein, carbohydrate, fats, vitamins and minerals) are both important and indispensable in fish farming for the optimal growth and health of the fish (Nwabueze and Nwabueze, 2011). Supplemental diet do not contain a full complement of nutrient needed but are used to help fortify the naturally available diets (Riche and Garling, 2003) reported that fish reared in intensive tank systems requires all nutrient in a complete pelleted diet since natural food is limited and fish cannot forage freely for natural foods. This has the advantage of high quality and consistency of diet. Good nutrition in fish production system is essential to economically produce healthy and high quality fish products for human consumption.   

Fish feeds are constantly in contact with environmental organisms and become readily colonized by various microbial species. According to FAO (1987), environmental factors during storage predispose the fish feeds to microbial spoilage. The presence of bacteria in feeds causes their decomposition and subsequently high disease which may be transferred to man when consumed (Karine, 2010). Fungi contamination of fish fed has been reported to result in aflatoxicosis (Asley,1970). Aflatoxins are chemicals produced by fungi like Aspergillus flavus and Aspergillus parasiticus commonly known as mold (Sotolu et al.,2014). Mold infested fish feeds have been reported to impact negatively on the growth of fish (Sotolu et al.,2014). Aflatoxin in fish have been known to be capable of having carcinogenic effect on human consumers of contaminated fish. The occurrence of these microbial strains in fish feeds have been reported to depend on the storage conditions of the feeds particularly temperature.

The quality of fish feeds and the hygienic levels of technological process employed during feed formulation determine the level of risk of microbial contamination aided by temperature. According to Zmyslowska (2000), storage conditions especially temperature and humidity are important factors affecting microbial quality of fish feeds. Improper storage temperature may prolong survival of the microorganisms in fish feeds by enhancing their multiplication and production of toxic substances which may be injurious to fish and consequently to consumers.

Also microbiological composition of the fish feed has a big influence on the weight gain and fish health condition. Especially if there are harmful microorganisms present in the feed that destroy the health condition of the fish which results in the disorder in the digestive metabolism leading to the decrease of the new born fishes or total death. Microbiological status has a cosmopolitan character also because the fast reproduction of the microorganisms can lead to over reading the upper boundary of tolerance for maintaining the health condition and can cause the decrease of the fish production or death, which is a total disaster for the fish farm. That is why it is very important to examine the microbiological status on the fish farm (Dalmacija, 2003).

Rearing of fish in concrete tanks using artificial diet has become a common practice in Umuahia. Several outlets for sale of artificial fish feeds now exist. There is a need to investigate the microbial flora of fish feeds sold in Umuahia. This is to forestall contamination of fish feed and by implication prevent transmission of harmful toxic effects on human consumers of fish.