Enhancing Red Color Quality in Koi Fish: The Role of Roselle Extract

Koi fish, prized for their vibrant colors and graceful appearance, hold significant economic value in the ornamental fish industry. The beauty of koi fish is often assessed based on color quality, behavior, body shape, and overall health. Among these factors, color quality stands out as a crucial determinant of the fish’s market value. Consequently, optimizing color quality becomes paramount, with nutrition playing a vital role in achieving this goal.

One significant factor influencing the color quality of koi fish is the nutritional content of their feed. Adding color-enhancing agents to their diet can boost pigment levels in their bodies, thereby intensifying their hues and maintaining color vibrancy over time. Among the various colors, red stands out as a key determinant of koi fish’s value.

Coloration in fish is primarily attributed to pigment cells or chromatophores present in their dermis, both above and below the scales. Natural colorants, derived from plants and animals, offer a safe and effective means of enhancing coloration without adverse side effects. Red pigments found abundantly in nature can be classified into two main groups: carotenoids and anthocyanins. Anthocyanins, a type of flavonoid pigment soluble in water, contribute red, blue, and purple hues commonly found in flowers, fruits, and vegetables, including Roselle. Roselle contains approximately 51% anthocyanins along with around 24% other antioxidants.

This study explores the effects of Roselle extract supplementation in koi fish feed, with varying concentrations tested: P1 (1% Roselle extract), P2 (3% Roselle extract), P3 (5% Roselle extract), and a control group (without Roselle extract). The feed dosage administered after mixing with Roselle extract amounted to 5% of the fish biomass. The study measured red color quality using a Toca Colour Finder (TCF) and assessed the fish’s survival rate, with water quality parameters serving as supportive indicators.

The results indicate that the addition of 5% Roselle extract yielded significantly higher red color quality compared to lower concentrations or the control group. This enhancement is attributed to the anthocyanin pigments derived from Roselle extract, which stimulate pigment formation in koi fish. The intensified coloration results from morphological and physiological changes in chromatophore cells. Furthermore, koi fish fed with Roselle extract-enriched feed demonstrated a 100% survival rate, whereas the control group experienced two fish mortalities during the four-week observation period. The high survival rate can be attributed to the antioxidant properties of Roselle extract, which contribute to the overall health of the fish.

In conclusion, Roselle extract proves effective in enhancing red color quality in koi fish, with the optimal dosage being 5% Roselle extract. This research underscores the potential of natural additives in improving ornamental fish coloration and highlights the importance of nutrition in maintaining fish health and market value.

Original article