What happens to the black pigment as your goldfish ages? Paul Green advises.
As goldfish age, their colour can change and they often become whiter, although the rate of this varies from fish to fish and I currently have a three year old Ranchu that is getting redder!
However, black is a different story as in twin- or tri-coloured goldfish, black is not a dominant colour gene and will often disappear over a period of time. Heat seems to play a part in this and the warmer the fish are kept the quicker the black colouration can disappear.
Goldfish can sometimes get an increase of black pigment (melanin) when they have been through a treatment or have been stressed. This is an outward sign of healing and means a normally red fish would also have black colouration on the head, body or fins. This temporary colour change can last a few days or sometimes a few weeks.
I have heard of many techniques for maintaining or improving the black colouration on goldfish. Access to direct sunlight works – and don’t feed any colour (red) enhancing foods!
All-black varieties like Moors present a different challenge as many take on a copper colour from the belly up, but I’ve seen some lovely coal black examples in recent years.
This article was first published in the November 2009 issue of Practical Fishkeeping magazine. It may not be reproduced without written permission.