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The global ornamental fish trade is expanding in response to increased demand for indigenous fish on the global market, while exogenous carotenoids can improve colouration. The 60‐day trial investigated the effect of carotenoid supplementation, via Artemia, on colouration, growth and immunophysiology of Badis badis (dwarf chameleon fish). Carotenoid was enriched at 40 ppm (T1), 80 ppm (T2) and 120 ppm (T3) and compared with controls, C1 (unenriched) and C2 (oil‐enriched). Fish larvae (average weight 0.12 g) were fed enriched–unenriched Artemia in triplicates (5 × 3) in aquarium tanks (15 L). C1 and T2 had better skin colour (lightness and whiteness) in the posterolateral and caudal fins respectively. The value of redness (a*) in the anterolateral region was higher in T2 and T3 (p < 0.05). The anterolateral red index was higher (p < 0.05) in T2 and T3, whereas in the posterolateral and caudal fins, T1 and T2 were higher (p < 0.05). Compared to C1 and C2, the hue angle in carotenoid groups was found to be low (p < 0.05). No significant change in the growth performance was noticed (p > 0.05). Immune scores such as lysozyme and alkaline protease were highest in T3 (p < 0.05), whereas protease activity was highest in T2 (80 ppm). Stress biomarkers, viz., superoxide dismutase, catalase and malondialdehyde were low in groups fed enriched Artemia (p < 0.05). The integrated biomarker response means and star plot area were lower in the enriched groups (T1–T3), while T2 was the lowest. Overall findings reveal that dietary carotenoid improves the colouration and immune status, but fail to promote growth. Furthermore, 80 ppm enrichment dose improves the overall performance. The findings can help fish keepers improve fish colour and health status through carotenoid supplementation. [ABSTRACT FROM AUTHOR]

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Larval growth and survival of catfishes are largely influenced by the various biotic and abiotic factors. The present study investigated the effect of different light intensities and photoperiods on growth and survival of Ompok bimaculatus larvae. Three separate trials of 21 days each were carried out in an aquarium tank. The first trial investigated the embryonic changes (based on hatching rate and time) upon exposure to varied light intensity (0, 300, 500, 900 and 1200 lx) and photoperiodic regime (24l:0d, 16l:8d, 12l:12d, 8l:16d and 0l:24d). Subsequently, hatched‐out larvae were subjected to the aforementioned intensities (Trial II) and photoperiod (Trial III, intensity of 300 lx) for growth and survival attributes. Eight hundred healthy larvae (average body weight = 0.003 g) were randomly distributed into five treatment groups for the last two trials. Results suggest a higher embryo hatching rate and larval survival at 0 and 300 lx, whereas the largest larval growth was observed at 900 lx. In Trial III, survival was highest in 0l:24d and growth in 24l:0d and 16l:8d was higher (P < 0.05). Performance index was higher (P < 0.05) in both 0 and 300 lx light and decreased at higher intensities. The overall interpretation from the present study concludes that a completely dark rearing environment is recommended for better survival of O. bimaculatus although growth was compromised. [ABSTRACT FROM AUTHOR]

The effect of enriching live and formulated feeds with cod liver oil on hematoimmunological and enzymatic characteristics of Deccan mahseer (Tor khudree) fry was studied. The experiment consisted of four treatments: (a) an unenriched inert diet, (b) the inert diet enriched with cod liver oil, (c) the inert diet enriched with cod liver oil + unenriched Artemia, and (d) the unenriched inert diet + enriched Artemia. At the end of the experiment, the total erythrocyte count, total leukocyte count, hemoglobin, respiratory burst activity, glucose, metabolic enzymatic parameters (aspartate amino transferase, alanine amino transferase, lactate dehydrogenase, malate dehydrogenase) of liver and muscle tissue, and digestive enzymes (protease, amylase, lipase) in the intestine were examined. Fry fed the unenriched inert diet+enriched Artemia had the best immune status with significantly higher erythrocyte and leukocyte counts, hemoglobin, and respiratory burst activity, and lower blood glucose. In addition, activity of aspartate amino transferase, alanine amino transferase, and malate dehydrogenase was higher and lactate dehydrogenase activity was lower in fish fed this diet. Protease, amylase, and lipase also rose due to enrichment of the live Artemia fed together with the inert diet. Overall results indicate that immune and enzymatic function are improved when T. khudree fry are fed a combination of fish oil-enriched Artemia and unenriched inert diet. [ABSTRACT FROM AUTHOR]