How to Tell the Sex of an Angelfish
- 1). Note the body structure of the angelfish. Although it is not a definite way to determine the sex of an angelfish, observing its body structure can provide a clue as to whether it is male or female. Males generally grow more quickly, are larger than females and have a hump on their crown, the area located directly above their eyes. Females, on the other hand, sometimes possess a straighter line from the base of their dorsal fin to their lips, and form a 100- to 110-degree angle from the forward edge of the belly to the anal fin. Male angelfish form a larger angle, ranging from 120 to 150 degrees.
- 2). Watch their behavior. Male angelfish are more territorial than female angelfish. If one of the female angelfish becomes gravid (filled with eggs), all of the male angelfish will form a papilla, a small, pink protrusion under their belly, and any fish that do not are either females or unhealthy males.
- 3). Observing the spawning process is the only sure way to determine the sex of an angelfish. When mating, the male has a much smaller, thinner breeding tube while the female has a thicker, larger tube, which is located between the ventral and anal fins. As the female lays her eggs, her papilla protrudes and the eggs shoot out in a straight line. Afterward, the male swims over the eggs, touching them with his papilla to fertilize them.
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