Incorporating Sweet Lime Peel (Citrus limetta) Powder in Gold Fish (Carrasius auratus) Diets for Improvising Colour Stability in Home Aquarium

The ornamental fish industry is a rapidly growing sector, contributing significantly to global trade and aquaculture. Among various ornamental species, goldfish (Carassius auratus) is one of the most widely bred and aesthetically valued species due to their diverse coloration, adaptability, and ease of maintenance. The coloration of these ornamental fish is a critical factor influencing their marketability and consumer preference. The use of natural carotenoids in fish feed to intensify the colouration has become a preferable as well as profitable choice for fish farmers to meet the demand of radiant ornamental fish within budget. This study investigates the effect of sweet lime (Citrus limetta) peel powder as a natural dietary carotenoid source on the pigmentation and growth performance of ornamental goldfish (Carassius auratus). Goldfish were fed formulated diets supplemented with varying concentrations of sweet lime peel powder (50–150 g/kg i.e. 5−15%) over a 60-day period. Growth performance parameters, including weight gain, specific growth rate (SGR), and feed conversion ratio (FCR), were analysed parallelly with total carotenoid deposition in muscle and fins. Results indicate that fish fed with 8–10% dietary carotenoid supplementation showed optimal pigmentation enhancement and carotenoid deposition, while excessive supplementation beyond 12% showed reduced efficiency. Statistical analyses confirmed significant differences in carotenoid accumulation across treatments (p < 0.05), with peak deposition observed in the 10% supplementation group. However, no significant differences in growth performance were detected among treatment groups. Water quality parameters remained stable throughout the study, ensuring optimal rearing conditions. The findings highlight the efficacy of sweet lime peel as a cost-effective, natural carotenoid source for enhancing goldfish coloration without compromising growth or survival. This study contributes to sustainable aquafeed development by utilizing fruit waste for ornamental fish nutrition.