it was blood
if your goldfish lives in you then yes
Yes.
A goldfish with a red head has a distinct coloration that sets it apart from other goldfish. The red head is a unique feature that makes it easily recognizable.
All goldfish are freshwater.
No, goldfish should only live with goldfish with a few small exceptions that do not include red ear sliders.
No they do not. The water lice are parasites and will drink the blood of the goldfish.
yes, but it may kill the goldfish
It is most likely that the food you are feeding it with, has red dye in it.
Red blood cells have to pass through capillaries in a single file so the cells move fairly slowly. Because arteries have enough space to allow multiple red blood cells to pass side by side, blood flows fairly quickly. Therefore, blood moves more rapidly in arteries.
Maybe you are seeing natural red rays in the fishes fins? If not then there is something wrong with the water. Change some (50%) water daily and see if the red markings disappear. Dont change all of the water.
a goldfish