Originally Posted by LauraEverhart
Ah, I was under the impression that there were breeding gurus who could identify based on physical characteristics... thanks for the reply, though!
What has happened over the years is that some physical characteristics that used to be found only on one gender are now found sometimes on the opposite gender or not at all. So it is very difficult to sex fish 100% anymore just by pictures. If these were wild fish, I would feel more confident in giving you my gender thoughts. Watching them spawn is the only guaranteed way to positively identify genders these days.
There is something that you can do however, to increase the chances of correctly identifying genders.
In the morning, prior to the first feeding of the day, look down from above at your fish. A female holding eggs will have a bulge in the abdominal region of the body. These are the eggs making that bulge. If there is no bulge and the body line is smooth all the way down, this is most likely a male. This fish will also most likely be larger than the female if these fish were bought together and at the same size. Sometimes the bulge will be slight especially with new breeders but it will be there if there are eggs in there.
This method only works before the first feeding of the day. Any other time of day could be confused with food in the stomach. It must be before the first meal of the day ( and at least 6 hours after their last meal. ) If you can get a full frontal view, you will see the flatness of the male along the side better but the above view is still the best for sexing females.
Hope this helps