how do you tell the sex of a goldfish???

Question

also my goldfish is not realy eating

Answer 1

Check this site out for help with sexing your goldfish,
http://www.bristol-aquarists.org.uk/goldfish/info/sexing-fs.htm

How long have you had your fish? They may just be getting used to the new surroundings and don't want to eat yet.

Answer 2

What is the temperature of your tank? Goldfish need 55-65 degrees to be healthy. Also gold fish need lots of Dissolved Oxygen. This only enters the water in the form of movement against air...i.e. waves, waterfalls, filters, powerheads etc.

Gold fish sexing is quite simple (Depending on your type).
Midline ridge: Males develop a ridge on their undersides that starts in back of their pelvic fins and ends at their vent opening. The ridge is absent or much smaller on females. (Firmness of Abdomen: For my heavy-bodied goldfish, the area between pelvic fins and the anal fins is fairly pliable on the females. For the males, this area is usually very firm.
Vent shape: According to several books, you can sex goldfish based on vent shape. I haven't been able to figure this out yet, so I won't confuse with an attempt at explaining what I have read.
Pectoral fin shapes: For short-finned varieties, males have longer, more pointed pectorals with a stiffer leading ray. Females have more rounded pectorals and shorter, finer front fin rays. For long-finned breeds, the fin shape is hard to judge. But the first ray length and thickness should still be somewhat different. This works pretty well.
Other features: Some other characteristics that I think would be very hard for beginners to make use of: males are alledgedly brighter colored, more active, and have longer fins.
Using a known female: introducing a fish known to be a female into a tank of goldfish of unknown sex. the males will all "check out" the new female, while the females will show no interest.

Answer 3

the fact your fish is not eating is really more important than the gender, i would dose with a broad spectrum antibiotic and give it at least a week,

that being said you cant sex a baby goldfish, but after a 3 inches or so you can wait until spring and come april-mayish males will get little white bumps in thier gills, in face one of my oranda is already developing them

you can also compare the cloaca (vent, poopy hole) with another couple goldfish, males have more of a line and females have more of a mound
good luck

Answer 4

If you see baby fish coming out of it.