Scientists uncover the cellular mechanisms behind fish colour patterns

Bitterfing (Rhodeus ocelatus) | Wikipedia

Colour patterns in fish are a combination of pigment cells, genetic control, and the interactions that occur between them. These patterns play crucial roles in communication, camouflage, mate choice, and species recognition.

A team of researchers from China has now identified how different pigment cells interact to create the striking colour patterns of the bitterling (Rhodeus ocelatus), a freshwater fish widely distributed in East Asia and often used as a model species in ecological and evolutionary studies.

The study, published in Frontiers in Cell and Developmental Biology, shows how melanophores (black/brown pigments), iridophores (reflective/iridescent pigments), and xanthophores (yellow pigments) are organised and rearranged during development to form the fish’s characteristic patterns.

According to the authors, “colouration in fish is formed by the interactions among different types of pigment cells, such as melanophores, iridophores, and xanthophores.” The researchers emphasise that these patterns are not the result of isolated cells acting independently, but of continuous communication and balance between them. They conclude that “interactions between pigment cells are essential for the maintenance and alteration of the colour patterns.”

Using advanced imaging and cell-tracking techniques, the team demonstrated how the distribution and movement of these cells shape the visible stripes and patches of R. ocelatus. This discovery highlights the bitterling as a valuable model for studying vertebrate pigmentation. As the authors note: “Our findings suggest that Rhodeus ocelatus could serve as a valuable resource to better understand pigment cell biology.”

Beyond its biological interest, the research provides insights directly relevant to aquaculture. In ornamental fish farming, colour patterns are a key factor in market value. A deeper understanding of the mechanisms regulating pigmentation could help optimise breeding strategies and improve fish welfare, as stress, diet, and environmental conditions also influence pigment expression.

This study is useful to better understand the genetic and cellular basis of fish colouration, while also offering perspectives that connect fundamental biology with practical applications in aquaculture, ornamental breeding, and biomedical research.