Seahorses Sticklebacks and Relatives: Gasterosteiformes

Physical characteristics: The back, belly, head, and tail of leafy seadragons are covered with spines that support flowing skin that looks like leaves. These fish are greenish brown or yellow with stripes along the trunk. The head has a slight mask and dark blotches on the "leaves." These fish are about 14 inches (35 centimeters) long. The body is long and slender and is encased in ringlike bony plates. The head is long and is almost at a right angle to the body. The snout is very long. The tail is slender and grasping, like that of a monkey. Leafy seadragons have no pelvic or tail fins, lateral line, or scales. Pelvic fins, the rear pair, correspond to the rear legs of four-footed animals. The lateral (LAT-uhr-uhl) line is a series of pores and tiny tubes along each side of a fish's body and is used for sensing vibrations.

Leafy seadragons appear to float aimlessly in kelp beds, protected by their elaborate camouflage. (Illustration by Joseph E. Trumpey. Reproduced by permission.)

Geographic range: Leafy seadragons live along the southern coast of Australia.

Habitat: Leafy seadragons live in shallow water and down to about 98 feet (30 meters), usually sheltered among seaweed and reefs but also over sandy areas.

Diet: Leafy seadragons eat shrimp and lobster.

Behavior and reproduction: Leafy seadragons appear to float aimlessly in kelp beds, protected by their elaborate camouflage. They may move rhythmically back and forth in a manner similar to seaweed being swept by currents. Adults may gather in shallow bays in late winter to pair and mate.

When a male leafy seadragon is ready to mate, his tail becomes swollen and turns bright yellow, and he releases sperm onto his belly. The female deposits her eggs onto the male's belly, pushing them into place. Egg pockets then form on the male to fasten the eggs securely in place under his tail. After about eight weeks, the eggs hatch and the male deposits the young over a wide area.

Leafy seadragons and people: Leafy seadragons are aquarium fishes that also attract recreational divers who want to see them up close.

Conservation status: Leafy seadragons are not threatened or endangered. ∎