This is because they are trying to breed or fighting but they will fight to death
Female Fantail goldfish can not get pregnant they lay/scatter eggs when they are chased by males . So you have nothing to worry about.
Female goldfish are slightly bigger than males
Females have a protruding anus, while males don't.
um, no, not at all.
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.
Where their poop comes out. If it comes out horazontilly, it is a male. If it comes out straight, it is a female. Males are the most common.
While it's rare, some goldfish can be aggressive and may nip fins. Otherwise males will chase females in the tank if the female is full of eggs. If this is the case, the male will poke his head against her side and her belly to try & get her to release eggs.If there is one specific fish that is being chased, you may need to separate that fish from the others for it's own health; if there is one specific fish that is constantly chasing the others, then you may need to separate that one from the rest.
Unlike humans, telling the gender of a goldfish actually takes some knowledge. Do not pay attention to the color or the fins. Female goldfishes are actually bigger than the males (especially with their eggs). Males have mid-line ridges on their undersides. With all these in mind, the easiest way to tell is by their spawning time. The female opening will be bigger and heavier.
yes it will take 1 week for them to hatch
Males will start fertilizing the eggs that come from a female goldfish's body immediately. Once the eggs are released the male will follow up and fertilize them.
Determining the sex of a goldfish is not always easy. If it's breeding season, a male will get what are called breeding stars on their gill plates; they look like tiny white dots. Sometimes the males will have them for longer, but that's not always the case.The easiest way of course would be if a female releases eggs in your tank after being chased by a male.
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.