Weedy seadragons usually become mature in their second year of life when they are fully grown. The breeding season for weedy seadragons is in Australia’s early summer months. One brood is produced each season. Like their seahorse relatives, male seadragons brood the eggs. However, the eggs are incubated on the underside of the tail on a brood patch instead of in a brood pouch. The female lays 250-300 eggs that are 4 mm (0.16 in) in diameter and 7 mm (0.3 in) long. She deposits them in the skin of the male to be fertilized, covering most of the under and sides of his tail immediately behind his anus. His skin, soft at the time the eggs are first embedded, becomes hardened to form a cup around each egg to hold it securely for the 6-8 weeks incubation. Each egg receives oxygen via the cup’s blood-red tissue. The eggs are bright pink when freshly laid and darken as they develop. When hatching starts, the male releases only a few eggs at a time. He may take from hours to days to let go of the entire brood.
Fry unroll from their tight position in the egg capsule, coming out tail first. They have a very short snout, and lack leafy appendages. They settle out on the substrate in shallow water where they live off the still-attached egg capsule for about two days until their snout is more pronounced and they are ready to start hunting. They then fed on small zooplankton such as rotifers and copepods, eventually becoming large enough to hunt and eat mysid shri
