Hi folks
My
goldfish has a small bit of black colour on the top of his tail. It has always been there since i got him. its part of his natural colour, funnily it looks like hes a swordtail, because he has the same sword edge at the end of his tail fin. The past couple of days ive noticed that the rest of his fins have started to change a shade of black and lines of black colour have appeared on his fins. There is also a small bit of black under his eyes. What is this ? Is he changing to his natural colour with age ? He is still happy and as active as ever.
thanks
C W