Proximate compositions of five economically-important fish species from Lake Victoria and Lake Tanganyika, Tanzania were determined using standard methods and procedures of the Association of the Analytical Chemists. Samples of Lates niloticus, Oreochromis niloticus, Rastrineobola argentea, Limnothrissa miodon and Stolothrissa tanganicae were collected during the dry and rainy seasons (December 2012 to March 2013) and (June to September, 2013). Protein contents (17.35-21.44 g/100 g) were significantly (p<0.05) higher in wet seasons and lower (16.13 -19.77 g/100 g) during the dry season in all the species. Similarly, lipids contents were significantly (p<0.05) higher during the wet seasons (1.01 -3.19 g/100 g) and lower (0.79 -1.79 g/100 g) during the dry season in all the species, while carbohydrate (1.89 -4.46 g/100 g) was significantly (p<0.05) higher during the dry season in all the species. The present study showed that these species are good sources of protein in desirable quantities for normal growth, development and as a remedy to nutritional and health related problems. High contents of protein and lipid during wet season make the fish species desirable for consumption during this period. These fish species are therefore recommended to diabetic consumers due to their low carbohydrate contents.

Purpose Aquaponics combine aquaculture with crop production in a mutual system. In this experiment, the growth of Amaranthus in aquaponics with tilapia fish was investigated. Methods 500-liter water tanks containing tilapia fish at four initial stocking densities of 100, 150, 200, and 250 fish/m 3 were used in triplicates, with a view to evaluate vegetable yields as influenced by fish biomass to water ratio. 1 g of Amaranthus seeds were sown in a 1 m 2 planting trough, which contained gravel with a top layer of sandy soil. The pots were flooded with water from fish holdings by an aquarium pump. Results The germination rate of Amaranthus was not significantly different across the experimental setup (P > 0.05). The growth rate of Amaranthus was significantly higher with increasing fish density (P < 0.05). The average lowest and highest of shoots dry biomass yield recorded were 0.36 and 1.95 g/plant at 8 weeks after of sowing, and this corresponds to fish stocking densities of 100 and 250 fish/m 3 , respectively. A high positive correlation was found between the shoot dry biomass of Amaranthus and fish stocking density. The survival of tilapia fingerlings was not significant different, while the production levels were 5.62, 4.77, 4.57, and 4.00 kg/m 2 in 100, 150, 200, and 250 fish/m 3. Conclusions The growth of Amaranthus in this experiment demonstrated that the plant could effectively utilize the nitrogenous waste from fish tanks for biomass production, even at a higher concentration, while considerations for moderate fish density are only for fish health.

Comparative study was conducted to observe the growth performance, length and condition factor of Oreochromis niloticus fed with two different diets using standard methods and procedures. The fish were fed with two different formulated Kunduchi Locally processed Feed (KLF) for a period of six weeks. Maximum weight gain of (10.74 to 12.48 g) was recorded with Kunduchi locally feed (KLF) with specific growth rate of (5.56 to 6.37 % per day), while minimum w Feed (AAF) with specific growth rate of (5.14 to 5.73 % per day). observed during the whole experimental period. in the 'b' values among all the experimental ponds and the value of the exponent 'b' ranged from (2.38 to 4.03) indicating both negative and positive allometric growths. The condition factor 'K' of all the experimental fish was above 1.0 (1.53 fishes from all the experimental ponds. The use of locally processed formulated diet such as KLF is therefore recommended as a step in boosting the aquaculture sector.

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