The conventional assessment of the specific growth rate (SGR) avoiding intermediary data is highly criticized by scholars as to the data of the beginning and the end of the production cycle usually considered for the measurement. To evaluate the SGR, the study was conducted in six concrete tanks under an outdoor laboratory shed from 10th May to 29th July 2017. Tilapia (Oreochromis niloticus) fry was released at the rate of 8 fries per tank as per the recommended stocking density of 320 fishes/decimal in an intensive aquaculture system. To evaluate the experiment, sinking and floating feeds as treatment 1 (T1) and treatment 2 (T2) were used for feeding the fish, respectively. There were three replications for each treatment. During the experimental period, the feed was supplied at the rate of 20%, 15%, and 10% of the body weight in the 1st, 2nd, and 3rd months, respectively. The daily ration of fish was divided into two parts and delivered to fish in the morning and in the evening. Aeration facilities were installed for 24 hours using an air stone aerator. Digital balance was used for measuring the weight of fish in 3 days intervals to assume the trend of SGR while a customized scoop net was used to sample the fish minimizing the stress on the fish. The weight gains of fish were 126.08±5.65 and 132.23±1.29 for T1 and T2, respectively. The mean percent weight gain was found higher in T2 (1715.03±0.00) than in T1 (1639.43±0.00). Feed conversion ratio (FCR) in T1 and T2 were 1.97±0.11 and 2.13±0.18, respectively. The specific growth rates (SGR) of tilapia in T1 and T2 were 4.90±3.03 and 4.98±2.28 considering the data at the beginning and the end of the production cycle, respectively. However, the SGR for floating feed was higher at the initial stage of the production cycle and lower in the later stages. The SGR was almost static for sinking feed from the beginning to the end of the experimental period. The higher FCR in T2 was correlated with the lower SGR in the later stage of the culture period. This ascertains that the pre-determined required amount of feeding ration imparted by the farmers in case of floating feed which wastes the high-cost feed and money. Higher total production was obtained in T2 (1119.52 g) than in T1 (1070.19 g) with 100% survival in both treatments. Therefore, determining SGR in a specific interval might be a useful tool at the farmer’s level.

The growth and survival are considered as the crucial factors that should be taken into consideration in any aquaculture system. The experiment was aimed to evaluate the growth performance and subsequent survival rate of the rohu (Labeo rohita) and tilapia (Oreochromis niloticus). It is important to evaluate the growth responses in relation to Feed Conversion Ratio (FCR) and assessment of the total production of the culture unit. As per the recommended stocking density of 320 fishes/decimal in intensive aquaculture system 8 fry per tank was released to assess the growth performance, survival and production of both rohu (T1) and tilapia (T2). During experimental period, there were three replications for each treatment and feed was supplied at the rate of 12%, 8%, and 4% of the body weight of rohu and 20%, 15%, and 10% of the body weight of tilapia in 1st, 2nd and 3rd month for T1 and T2, respectively. The initial weight of individual tilapia was 7.52±1.81 gm and 14.75±0.19 gm for T1 and T2, respectively. The mean final weight was 44.01±4.03 g for T1 and 139.94±1.29 for T2. The weight gains of fish were 36.49±4.09 gm and 125.19±1.29 gm for T1 and T2, respectively. The mean percent weight gain of tilapia was higher in T2 (1715.05±0.00) than T1 (485.23±0.00). The Specific Growth Rates (SGR) of T1 and T2 were found 4.98±2.28 and 6.26 ±3.83, respectively. There was significant difference (p>0.05) in term of SGR between the treatments. Feed Conversion Ratio (FCR) in T1 and T2 were 2.86±0.14 and 2.23±0.18, respectively. Higher total production was obtained in T2 (1119.52 gm) than T1 (278.19 gm) with 100% survival in both the treatments. The water quality parameters for both of the species were within the suitable range. This study reveals a promising arena for fish culture in tank-based intensive aquaculture system as an efficient way of overcoming the scarcity of water and land. This culture system may be an excellent way of producing fish in a small parcel of land with securing the propitious production and expected outcomes within a limited period of time.

Wetland environments in Bangladesh, such as rivers, lakes, ponds, beel, baor, and haor, are critical for the feeding, spawning, breeding, and nursing of at least 253 fish species, as well as a variety of freshwater fish and prawns. In addition, they support a number of rural people and provide habitat for a multitude of migrating birds. Bangladesh’s wetlands are classified as freshwater wetlands, saltwater wetlands, and artificial wetlands, with haors belonging to the freshwater wetlands group. Haor is a marshy wetland area that looks like a bowl or saucer. It is inundated for seven to eight months during the wet season, similar to a massive inland sea, and then divides into beels during the dry season. Apart from giving migratory fish and bird species breeding, nursing, and feeding habitats, it boasts around 154 native fish species from 35 families and 12 orders. The biodiversity of fish in haor wetlands has been experiencing a decline due to factors such as overexploitation, environmental degradation, and the persistent challenges posed by climate change. To effectively manage the haor wetland ecosystem, it is strongly recommended that an ecosystem-based co-management approach be adopted. This should involve the active participation of the local community, the establishment of sustainable fishing practices, and the promotion of alternative livelihoods for deprived harvesters who are heavily reliant on these resources. This review paper proposes a simple and practical approach to studying the haor wetlands, the current state of fish biodiversity in the various haor ecosystems of Bangladesh, and related challenges.

Aquaculture is the most vital, dynamic, and rapidly expanding food-producing sector in comparison to other food-producing industries. Nevertheless, aquaculture output is impeded by a number of viral, bacterial, fungal, and parasitic diseases. In order to comprehend the current circumstances of the use of chemicals and antibiotics for the management of fish health in freshwater aquaculture in the northern region of Bangladesh, the current investigation was carried out. Through questionnaire interviews, a market survey, and focus group discussions with the intended target group, data was collected. A comprehensive outline of various chemicals, antibiotics, and aqua drugs frequently used in freshwater aquaculture in the northern region of Bangladesh have been provided in the present study. These drugs and chemicals have been recorded to be applied in freshwater aquaculture for a variety of purposes, including disease treatment, growth enhancement, water quality improvement, and oxygen level improvement. Mostly, Bioaqua, Zeolite, Zeolite Geotox, Aquakleen, Aquaboost, Pond Life, Zeo Prime were used for water quality management; Oxy more, Aqua oxygen, Bio Care, Oxyflow to improve dissolve oxygen level; Aqua bind, Nutrimax, Protox aqua, Aquazyme, Megavit-Aqua, Aqua Boost, Aqua-C as growth promoter; ; Polgard Plus, Virex, Timsen as disinfectant; Oxysentin 20%, Bactitab, Malachite Green, Formalin, Aquamycine, Renamox 15%-vet, Acimox (vet) Powder, Cipro-A vet, Ciproflox were used against the prevalence of fish diseases. The improper utilization of aquatic drugs has been linked to various concerns, including inadequate information regarding chemical usage, insufficient dosage, improper application technique, and indiscriminate antibiotic usage.

Traditional assessment of specific growth rate (SGR) using the data of the beginning and the end of aquaculture production cycle, avoiding intermediary data, is criticized as misleading way by the scholars. However, by knowing SGR in different stages of fish growth, the utilization of feed by fish can be well known. The study was conducted with aim to assess SGR of Tilapia in six concrete tanks for 90 days from 8th May to 10th August, 2017. Tilapia (Oreochromis niloticus) fry was released at the rate of 4 fry per tank equivalent to the stocking density of 160 fishes/decimal as of the semi-intensive aquaculture system. Sinking and floating feeds were used for feeding the fish in T1 and T2, respectively with three replications for each treatment. During the experimental period, feed was given at the rate of 20%, 15% and 10% of the body weight in 1st, 2nd and 3rd month, respectively. Moreover, aeration facilities were installed for 24 hours using air stone aerator. The weight of fish was recorded using digital balance in 3 days interval to measure SGR. The water quality parameters i.e., temperature and dissolved oxygen (DO) were recorded twice daily. The weight gains of fish were 49.90±2.40 g and 63.12±4.97g for T1 and T2, respectively. The mean percent weight gain of Tilapia was higher in T2 (747±0.00 g) than T1 (253.51±0.00 g). Feed conversion ratio (FCR) in T1 and T2 were 1.70±0.07 and 2.53±0.20, respectively. Considering the data at the beginning and the end of the production cycle, the SGR (% per day) of Tilapia in T1 and T2 were 6.27±3.27 and 6.26±3.83, respectively. The SGR for floating feed was higher at the initial stage of production cycle and lower in the later stages. For sinking feed, SGR was almost static from the beginning to the end. The higher FCR in T2 correlated with the lower SGR in the later stage of the culture period. This confirmed that farmers using floating feed with pre-determined amount of feeding ration, waste the expensive feed and money. Higher total production was obtained in T2 (830.96 g) than T1 (610 g) with 100% survival in both treatments. Therefore, determining SGR in a specific interval, at least 15 days interval, might be the efficient feeding practice of Tilapia farmers.

Vitamin C is an essential micronutrient that cannot be synthesized by fish and must be present in fish diets for proper functioning of the physiological conditions. It is required for the biosynthesis of the collagen which is a pre-requisite for the formation of connective tissue and increases the absorption of iron in fish. It prevents various diseases; it is soluble in water and is easily oxidated by heat, light and metal. Most animals can generate vitamin C in sufficient quantities for normal growth and function, but many fish cannot because they lack the enzyme L-gulonolactone oxidase for its manufacture. Vitamin C facilitates the absorption of iron and is necessary for a maximum rate of immune responses and enables a good response to stressors. This updated review presents a general outline of the possible physiological function of vitamin C for fish, with an emphasis on the information on growth performance, antioxidant activity, immune response and disease prevention of fish as well as the synergistic effects of vitamin C with other micronutrients. The diets supplemented with vitamin C promote the growth performance, improve the structure of the intestinal mucosal epithelium, and have a positive impact on the hematological parameter. The addition of different dietary vitamin C to the basal diets significantly improved the growth performance, antioxidant activity, immune response and disease resistance of fish. vitamin C in the aquaculture, having a solid understanding of the positive functions and mechanisms that vitamin C possesses is of the utmost significance.