Instructions
Check their eyes. Male angelfish usually have redder eyes than females.
Compare angelfish of the same age. Males are generally larger, but thinner in the belly.
Look for a bump on the head. Males will usually develop a bump or swelling on their head just over the eyes. Females may have a straighter line from the base of the dorsal fin to their lips.
Observe the area between the ventral and anal fins. When angelfish are ready to spawn, they develop a papilla, which is a small protuberance between the ventral and anal fin through which a female deposits her eggs and a male his sperm. A female will have a papilla about a quarter-inch long and flat across the end. The male papilla will be about the same length, but more pointed. The female will appear to have a fuller belly because of the eggs.
Make a final determination after the angelfish start spawning. By then, it should be clear which is a male and which is a female.
How to Distinguish Between Male & Female Angle Fish
Angelfish have been popular in home aquariums for many years. Originating in the Amazon River, angelfish have been bred into many varieties due to cross breeding in captivity. With proper diet, correct water temperature and pH balance, angelfish can live up to l5 years. They can breed easily provided they have adequate room. Distinguishing between males and females can be difficult before they have reached maturity and have paired off to begin spawning.