My lovely fish has started getting these marks/growths on him. I tried interpet goldfish disease medicine and it hasn't seemed to work as it is still spreading. First it was just on his tail but now there is one mark on his body
Sometimes he lays at the top of tank with his fins down but he is still eating.
I have had him for around 2 years And he has never been sick.
I've attached attached photos but I have more if needed