The female will have a black patch at the back where the babies come out of ,sometimes she may keep going to the top as she will be running out of breath alot but sometimes we dont notice and she may have a square belly at the front also if the male hangs around the female alot (underneath her)then that means she is ready to give birth soon because as soon as the fri(babies) are born then he will try and eat them ,so if you see any of them signs quickly buy a nursery tank and pop her in it.
She will be bloated and she is very likely to be making short dashes for no apparent reason. She will hover in various places in the tank with her fins vibrating quite rapidly and then zoom to somewhere else and continue the fast vibrations. Eventually when she makes one of her dashes you will see a tiny baby or two go down to the bottom of the tank in the area she has dashed from.
By performing an experiment
Danios are egg layers and can not get pregnant.
If you look at there bottom fin the males have a fin that sticks strait back where females are fan shaped.
You wouldn't ever be able to tell this, because carp fish do not get pregnant. Pregnancy implies carrying the young internally, which carp do not do.
If it has ever been anywhere near a male it will be pregnant (Gravid). It is very difficult to get a virgin livebearer. They can be gravid at 3 or 4 weeks old.
Goldfish of any type are all egg laying fish which means that they do not get pregnant
With a guppy you need to look at the gravid spot. This is a dark spot in the fish's belly. A large gravid spot indicates the fish is likely to be pregnant. You can tell how pregnant the fish is by how large the spot is. Sorry I have no experience with other species.
Mollie and vanessa are very close. frankie and vanessa. rochelle and mollie are close to. you can tell this from all the photos.
Orandas, or any other type of goldfish are egg laying fish, so they do not get pregnant
Your Oscar can not get pregnant. It is an egg layer. It will not be adult or mature until it is around 6 inches long.
Black moors are a variety of goldfish which are egg layers so they can't get pregnant.
Get a ovulation kit they tell you when your ovulating and increase the chance of getting pregnant good luck hope for the best in the future!