How do you tell when an angelfish is pregnant?

Angelfish are not mammals and do not give birth to live young. Rather, they lay eggs. When an angelfish is ready to lay eggs, she will become plump and her belly will become swollen. She will also begin to display a "breeding tube," which is a small, white tube that protrudes from her belly. When the eggs are ready to be laid, the female will select a suitable location, such as a plant leaf or a piece of driftwood, and clean it with her mouth. She will then lay the eggs in a single layer on the surface of the object. The male will then fertilize the eggs. The eggs will hatch in a few days, and the fry will be free-swimming.