If you are refering to a "Fancy tailed" goldfish. They only show a physical difference when they are in spawning condition (Springtime). At that time the male develops white spots on his gill plates (and sometimes his pectoral fins). The female develops a chubby tummy.
bass clef its obvious
The males are the colorful ones with the fancy tails. No fancy tail, you have a female, they are dull and usually a brown color.
in male fighter fish there is very deep colour and in female there is very fead colour female have a egg sack but males dont have
their role in reproduction. Females lay eggs and the Males...fertilize them.
Here are two that I was able to find. on the left is a reagular (female silver molly) on the right is a (fancy tail lyretail female sailfin molly)
what is the difference between fish farming and a fishing
A male Reed fish will have 12-16 anal fins, where a female will have only 8-12. Also, if you want to be picky, only the female will lay eggs!
It depends on the species. There are at least three different species commonly called 'Gourami'. In the case of Colisia sp. and Helostoma sp. the male is much more colourfull than the female. In Trichogaster sp. the main difference is in the fins. The males have much longer flowing fins than the female.
They have virtually no sexual dimorphism. Just by looking at them you will see no difference between the sexes.
There is no one specific way to tell the difference between male and female fish. Different species have different ques, and in the vast majority of fish, there is really no reliable external way to tell a fish's sex.
There is no specific research that I am aware of to indicate a dimorphism between male and female fish scales. Certainly there is no obvious difference that can be seen by the human eye.
The Gravid female will have the dark "gravid spot" in front of her vent. I can however assure you that if there has been a male in the same tank with a female guppy for any reasonable length of time she will be gravid.