I've seen a few threads regarding the sexing of angelfish lately so I wanted to help out a bit. I bred angelfish for 5+ years and discovered that there is really only one true way to sex angelfish. Some people will say that you can tell the sex of angelfish by their width or by the enlarged crown on their head, but from my experience these aren't always accurate. From my perspective there is only one true way to sex angelfish, the tubes.

Angelfish tubes will typically begin to appear in angelfish between 6 and 12 months of age. The tubes are the organ through which the eggs and sperm are delivered. Although on some fish they can be seen all the time, they are most predominant when the fish are breeding. Interestingly, tubes not on appear on angelfish that are actively breeding but also appear on angelfish that are simply in proximity to another pair that are breeding. As such many breeders will place fish of unknown sex into a tank with a breeding pair in order to encourage the dropping of tubes and proper sexing of the fish.

By examining the tubes of angelfish it is generally very straight forward to determine what sex the fish is. Tubes which appear sharp or pointed on the end (similar to the sharp end of a pencil) will be seen on male fish. Tubes which are more cylindrical (like the eraser of a pencil) are seen on female fish. As a reference I managed to get some close of photos of a one of my breeding pairs. Feel free to use these photos as reference. I hope this helps clear things up for those people breeding angelfish.