The Quintessence of Colour Enhancement in Ornamental Fishes:An Empirical Pathway Towards Rainbow Revolution

One of the greatest challenges in the ornamental fish industry is to replicate accurate natural colour of fishes in captivity. Numerous attempts to preserve colour in captivity have been ineffective in reducing its fading, making it an important determinant in the selection of ornamental fish species for trade in terms of saturation, brightness and hue. Colour development of ornamental fishes has been widely studied, yielding curious insights about evolutionary genetics and having a discerning role, either as deceptive or attractive (aposematic) signals in mating as well as in camouflaging (Delphic) patterns during predator–prey interactions. This article discusses colour enhancement strategies with reference to nutritional interventions through carotenoid-rich feed ingredients, genetic manipulation or injection of colour in subcutaneous layers of the skin. An insight into the mechanism of pigmentation shows that motility and pigment dispersion of chromatophores are the two drivers by which fishes control integumentary colour variation. Research on colour development and its enhancement has witnessed novel techniques to support the ornamental fish industry. Therefore, this article also sheds light to answer questions on various issues pertaining to environmental and physiological effects on colouration. It attempts to provide insight on potential research areas, with caution on ethical and legal issues to ensure sustainability, so as to restrict risks of unwanted inheritance of colour patterns. It also highlights the problems of identity crisis among conspecifics thereby bringing a ‘rainbow revolution’ to the ornamental industry.