To resurrect and establish a low-impact aquaculture practice, gel-based feed applications hold promise. Gel feed is viscoelastic, nutrient-dense, hard, flexible, and appealing, and can be moulded into appealing shapes to ensure rapid acceptance by fish. The purpose of this research is to create a suitable gel feed using various gelling agents and to evaluate its properties and acceptance by a model fish, Pethia conchonius (rosy barb). Three gelling agents, viz. starch, calcium lactate and pectin, were included at 2%, 5%, and 8% in a fish-muscle-based diet. The physical properties of gel feed were standardized using texture profile analysis, sinking velocity, water and gel stability, water holding capacity, proximate composition, and colour. The lowest levels of nutrient leaching protein (0.57 ± 0.15%) and lipid (14.3 ± 14.30%) were observed up to 24 h in the underwater column. The highest score for overall physical and acceptance characteristics was noted for the 5% calcium lactate-based gel feed. Furthermore, a 20-day acceptance feeding experiment was conducted using 5% calcium lactate to examine its suitability as fish feed. The results indicate a better acceptability (3.55 ± 0.19%) and water stability (−2.5 ± 2.5%) of the gel feed compared to the control, with an improvement in nutrient losses. Overall, the study provides an insight into the application of gel-based diets for ornamental fish rearing, besides ensuring an efficient nutrient uptake and minimal leaching to establish a clean aquatic environment.

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Asian catfish, Clarias magur (Hamilton, 1822), known as magur, is a popular food fish in Asian countries because of its high nutritional and medicinal value. Aquaculture of magur is constrained by non‐availability of seed due to very high mortality during the early larval stages. The strategies to enhance the larval survival during the early stages could be a major step in enhancing the seed production of this species. So, the aim of the present study was to assess the effect of highly unsaturated fatty acids (HUFA)‐ and vitamin C‐enriched infusoria on the growth and survival of C. magur larvae. Eight‐day‐old larvae with an average weight of 3 mg and length of 5 mm were stocked in plastic crates (30 x 20 x 18 cm) each containing 40 litres of water. A total of 16 crates were used in experiment and in each crate 100 larvae were stocked. The larvae were fed three times daily with HUFA, vitamin C, both HUFA and vitamin C and un‐enriched infusoria @ 9–10 numbers per ml of rearing water for 30 days in four different treatment groups. The proximate analysis of different enriched and un‐enriched infusoria showed the highest (84.25%) moisture content in HUFA‐enriched Infusoria, and the highest percentage of crude protein (9.80%), crude lipid (3.50%) and ash content (0.78%) in vitamin C‐enriched Infusoria. The survivability analysis showed the highest survival in the treatment group fed with HUFA‐enriched infusoria (49.25%) and the lowest in the control group (18.25%). This indicates that the enrichment of infusoria with HUFA could increase the survival rate significantly. The highest body weight gain (55.75 mg) was observed in HUFA‐enriched group but not significantly different from the control group. The study indicates that the enrichment of infusoria with HUFA have a significant influence on larval survival.

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