The study was performed in earthen ponds situated in North-Nile Delta, Egypt and adopted two fish farming systems. The first system was the feed fish farm that depended on pelleted diet (25% crude protein) as feed input, while the other system was the fertilizer fish farm which utilized both organic fertilizer and crushed macaroni as supplementary feed. Each system had four replicate ponds (8400 m 2 each). The experiment duration was one year, including four months of overwintering. Nile tilapia (Oreochromis niloticus), mullet (Mugil cephalus) and catfish (Clarias gariepinus) were cultured in each pond at initial weight of 2, 30 and 5 grams, respectively. Samples were collected to determine water quality, plankton abundance and fish growth performance. The results showed that the fertilizer fish farm had significantly high levels of pH, dissolved oxygen and total nitrogen content (TAN, NH 3 , NH 4 , NO 2 and NO 3) (P<0.05). Significant increase (P<0.05) in phytoplankton and zooplankton abundance was observed in the fertilizer fish farm compared to the feed fish farm. Within different species, catfish had the highest daily weight gain followed by tilapia and mullet, respectively. Within the two compared systems, farmed fish in the feed farm had higher average daily weight gain and specific growth rate. The feed fish farm had significantly (P<0.05) higher production and higher total income, while the fertilizer fish farm had higher net income and lower total production costs.

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The study was conducted in two fish farming systems in earthen ponds located in North-Nile Delta, Egypt. The first system was the feed fish farm that depended on pelleted diet (25% crude protein) as feed input, while the second system was the fertilizer fish farm which used both organic fertilizer and crushed macaroni as supplementary feed. Each system was replicated in four ponds (8400m 2 each). The experimental period lasted from July 2014 to June 2015, including four months overwintering. Nile tilapia (Oreochromis niloticus), mullet (Mugil cephalus) and catfish (Clarias gariepinus) were cultured in each pond at initial weight of 2, 30 and 5 grams, respectively. Water, sediment and fish samples were collected to detect the heavy metals concentration. The results showed that heavy metals concentration in water, sediment and three organs of fish species were significantly (P<0.05) different between the feed and fertilizer fish farms. The pond management affected the content of heavy metals in water, sediments and fish. Accumulation of iron in water, sediment and three organs of fish were higher than other elements. Accumulation of cadmium and lead in water, sediment and three organs of fish were less than other elements. Accumulation of heavy metals in liver and gills were higher than that of muscles in all fish species. Metals concentrations in the edible part of farmed fish were within the permissible level for human consumption proposed by various international standard organizations.