Rural fish farming is being promoted as a good source of protein and income diversification to fight poverty and inequality. However, its actual contribution to these rural households and local community at large is little known. Through interviews with 89 farmers’ and 6 key informants, we examined the contribution of rural fish farming to local farmers’ household income and investigate farmers’ perceptions, opportunities, and constraints towards fish farming in six districts of Tanzania. Results indicated that fish farming contributed on average 13% to household incomes and that it explained 5% of the variation of the household income while 84% of the variation was due to non-fish sources. The majority (79%) of the farmers wanted to continue with fish farming, 9% planned to quit, and 12% had not decided whether to continue or not. Conclusively, much higher aquaculture contribution towards rural development could be obtained if appropriate measures are taken.

An investigative field survey was performed to gather baseline data on locally available feed ingredients and fish farming practices in different regions of Tanzania. More than 80% of respondents relied on locally available feed ingredients as a major feed supplement for their cultured fish, with maize bran being the most commonly used feed ingredient in all regions. Crude protein content in most analyzed local feed ingredients was medium-high, while crude fat content was high in some animal and agricultural by-products, and medium-low in other ingredients. Most respondents were males and the majority of fish farms were owned by individuals. Earthen pond was the most common fish farming system in all regions except Dar es Salaam. Semi-intensively mixed-sex tilapia monoculture was the dominating fish farming practice. The results of the survey presented provide a good platform for future development of culture systems and feeding strategies for tilapia in Tanzania.

Eight locally available protein source ingredients in Tanzania were selected for assessment of apparent digestibility (AD) in tilapia Oreochromis niloticus, using faeces samples collected by siphoning or stripping. The selected protein source ingredients were Lake Victoria sardines (FM), brewers spent yeast (BSY), moringa leaves (ML), freshwater shrimp (FSH), marine shrimp (MSH), cattle blood (CB), duckweed (DW) and fish frames (FF). The AD (%) of dry matter (DM), organic matter (OM) and crude protein (CP) was unaffected (p > 0.782–0.901) by the faeces collection method (i.e., siphoning or stripping), with correlation coefficient (r) of 0.98, 0.99 and 0.93 between AD values for DM, OM and CP, respectively, following siphoning and stripping. The AD (%) of DM, OM, CP and gross energy (GE) in the test ingredients differed (p < 0.0001). The AD (%) of DM and OM was lowest in BSY and DW, followed in increasing order by ML, MSH, FF, FSH and CB. In general, the AD (%) of CP was high (>76%), but with a low value (46%) for DW. The AD (%) of GE was closely correlated (r = 0.96) with the AD of OM. In conclusion, FSH, MSH, CB, FF, BSY and ML have acceptable protein digestibility to be used in tilapia diet formulation.

Inland aquaculture operations are practised all over the world, contributing about 62.6% of all farmed aquatic animals. This venture is increasing worldwide and outpacing the global market demand for fish and fishery products driven by competition with other animals, over‐population and over‐exploitation of wild capture fisheries. These operations expand globally, associated with the degradation of the culture environment due to poor aquaculture management practices and algal blooms due to nutrient influxes as well as high demand of quality fish feeds of affordable price. To overcome these challenges, sustainable, healthy and environmentally friendly alternatives including probiotics application must be adopted to achieve better production, profitability and productivity as well as a resilient culture environment. In this review, information on potential applications of probiotics in aquaculture (inland aquaculture) focused on sources, safety, approved probiotics for aquaculture, characteristics of probiotics, mode of applications and its potential use on pathogenic microbes control, fish haematological parameters, growth performance and stress responses, water quality parameter, anti‐nutritional factors and feed digestibility, limitation of using probiotics in aquaculture and lastly future perspectives on the probiotics application in aquaculture industry were reviewed and compiled for future sustainable aquaculture production and productivity and environmentally friendly. The review has also highlighted all probiotics application and their approved authority for use in farmed freshwater fish (Nile tilapia Oreochromis niloticus, Catfish Clarias gariepinus, rainbow trout Oncorhynchus mykiss and common carp Cyprinus carpio) and their cultured environment worldwide. Therefore, the review has comprised all information on the potential benefits application of probiotics in an inland aquaculture for public documentation and also identifies gaps in the aquaculture industry that require further research and assessment.

Fish like other terrestrial animals, have specific requirements for individual minerals that support the growth and maintenance of normal fish health and other biological functions among different cultured fish species. These minerals can be either macro or micro minerals that are supplied to the fish body through diets or absorbed from their surrounding environment via skins, gills or alimentary tract. However, the bioavailability of these minerals to the fish body is influenced by several factors, including the intake level of the nutrient, interactions with other minerals or nutrients and cultured fish species. To enhance effective bioavailability to the farmed fish, sustainable, healthy and well‐mineral‐balanced diets must be adopted to achieve better fish growth performance, and a high survival rate for high production and productivity while ensuring the resilience of the cultured environment. In this review, the quantitative mineral composition of different mineral sources was reviewed and reported. In addition, mineral requirements in several cultured fish both freshwater and marine water fish species for five macro minerals (calcium, phosphorus, sodium, potassium and magnesium) and seven micro minerals (zinc, iron, copper, manganese, iodine, chromium and selenium) were compiled and reported. Nile tilapia is dominating freshwater cultured species in Tanzania, followed by catfish and rainbow trout, while milkfish is dominating cultured marine species practiced along the coastline from the Northern Tanga region to the Southern Mtwara region. Moreover, this review also covers information on the relationship between minerals and farmed fish, the mechanism of mineral absorption in fish and implications associated with bioavailability of minerals in both aquatic animal body and their surrounding environment, as well as mineral research in future perspectives in the aquaculture industry development. Therefore, the review comprises all this information on the importance of minerals and their bioavailability in farmed fish for sustainable aquaculture production and productivity.

The utilization of Taro leaves as fish feed is hampered by high levels of oxalates. An investigative study was carried out to assess the efficacy of soaking and drying method on oxalate content reduction in taro leaves. During this study, the taro (Colocasia esculenta) leaves samples were collected along the river bank and washed before transported to laboratory for further processing and analysis. The leaves samples subjected to different processing method (soaking and drying) were crushed or grinded into a fine paste or powder using pestle and mortar to obtain extract for oxalate analysis, respectively. The soluble oxalate content in all samples was extracted using acidic solutions, and then analysed by titration methods using potassium permanganate solution (LOBA Chemie, India). The insoluble oxalate content (calcium oxalate) was obtained by subtracting soluble oxalate from total oxalate. The results showed that soaked and dried Taro leaves contained low level of oxalate compared to unprocessed leaves. The oxalate content of unprocessed leaves was 43 mg/100 g WM, while that of soaked and dried leaves were 23 and 4.2 mg/100 g WM, respectively. Therefore, the study has proven the efficacy of soaking and drying on oxalate reduction in taro leaves before used in a fish feed formulation.