Male fish have claspers on their lower belly, so if the fish doesnt have these claspers, then it's a female. I dont know if it's the same with goldfish, but since they're fish, it probably is.
a goldfish that is Female
The female goldfish has larger tail fins, and most of their coloration is completely orange. On the other hand, the males are usually orange with white specks on their gills.
A male goldfish developes white spots when he is about to fertilize the females eggs. It could be possible that you have a male and a female! Congrats!!!
Only professionals can be sure of an answer to that but there is a way you can get a rough idea. The female tends to be larger(plump) than the male. This is because of her stored eggs. That too, but, males are more quick and hyper. Females tend to be calm and relaxing. The males will have small white bumps on his gill, while the female's belly is larger on one side because of eggs. Only one side.
They are spawning. The white dots just indicate the male is ready to spawn.
The difference between a male goldfish and a female is that the female is usually bigger and in spring and the male gains a white pimple type substance on it's gill flap also the female is more of a gold color and the the male is a silver color.
No
Female goldfish are usually bigger than male goldfish.
the goldfish that is being chased might be a female goldfish where as the others are male goldfish, so the female one gets battered around the tank and the fins and tail might shred it is a good idea to separate the single fish so it wont be attacked. i know this cause my Goldfish do the same XD Look for white dots on the cheek of fish that r chasing the other one. if it does have white dots its a Male hope that helped :)
Both sexes have gray/white underparts.
Possibly feces?