Angelfish are among the most beautiful of all aquarium fish. Experienced hobbyists may want to try their hand at breeding these beautiful specimens. Angelfish that are kept in good condition will generally spawn quite readily, but it is up to the fish owners to accurately determine the sex of the fish in their tanks. It is not always easy to determine the sex of an angelfish, but there are a few telltale signs.
Watch the Fins
Male and female angelfish look similar, and it can be quite difficult for even experienced fish keepers to tell the difference. The most pronounced difference between the male and female angelfish is the size of the tube located between the anal and the ventral fin. This tube will be much thicker in the female than in the male, but the difference is generally not easily visible until the fish have begun to spawn. Angelfish breeders will need to keep a close eye on their fish to notice the difference between the males and the females in the tank.
Swelling with Eggs
One of the surest ways to tell a male angelfish from its female counterpart is to watch for the telltale swelling of eggs. When the female gets ready to spawn, she will start to swell up with eggs, and by the time spawning gets underway that swelling will be quite pronounced. It is important for any hobbyist who plans to breed angelfish to keep an eye out for this swelling. After the female has been identified, the fish keeper can use the distinctive patterns on each fish to record which ones are males and which ones are females.
The only sure-fire way to determine the sex of an angelfish is to actually watch their fish as they spawn. Once the first spawning is underway, it will be quite apparent which fish is laying the eggs and which one is fertilising those eggs. After the sexes have been definitively determined, fish owners can use the unique patterns of each fish to record those sexes. Keeping accurate records will make it easier to set up special spawning tanks for the angelfish.