Goldfish has always been a favourite of aquarium owners who love to keep colourful fishes in it. Now there is good news for them as it has been proved that goldfish can be made more colourful by making natural plant pigment sources as part of their diet.

The study was conducted by researchers at Kerala University of Fisheries and Ocean Studies (KUFOS) school of aquaculture and biotechnology. The study stated that natural pigment sources can be incorporated into their diet (5%) as additives to enhance their colour.

Researchers used pigment sources from brightly coloured plant material like the peel of pomegranate, petals of African tulip tree flower, a commonly seen ornamental tree and red paprika. These were shade dried and powdered before mixing with commercially-available normal fish feed.

The experimental feed was given to the fishes for a period of 60 days at Kufos laboratory. The fishes were assessed for colour intensity, growth in length and weight, food conservation ratio (FCR) and specific growth rate (SGR).

The results were found to be encouraging. The study was conducted as colouration was one of the essential sales factor deciding the market value of ornamental fish. To achieve consumer acceptance and optimal price, the gold fish must ideally be pigmented to have an orange and red colour.