Seadragon
Seadragon Facts
| Size | 8-18 inches (20-45 cm) |
| Speed | Unknown |
| Weight | Unknown |
| Lifespan | 2-10 years |
| Food | Small crabs, plankton |
| Predators | Fish, crabs, rays |
| Distribution | Australia |
| Habitat | Algae beds, Seagrass meadows |
| Order | Syngnathiformes |
| Family | Syngnathidae |
| Scientific name | Phycodurus |
| Characteristics | Fish that looks like seaweed or seaweed |
Main Characteristics
Seadragons are small marine fish that look like kelp or seaweed. Their swimming abilities are limited, so they rely on camouflage as a means of protection from predators. Their camouflage is called mimicry and refers to imitating plants or other animals.
Species
There are only three species: the leafy seadragon, the weedy seadragon and the ruby seadragon. The latter was only discovered in 2015.
Distribution and Habitat
Seadragons live exclusively in Australia, along the coast in the south of the country. As a habitat, they prefer shallow waters, rocky reefs, algae beds and seagrass meadows.
Life Style
Seadragons tend to be solitary creatures. They float in the sea and wait for prey to come along so they can quickly snatch it up and swallow it.
Anatomy and Appearance
Physique
Seadragons have a long, narrow body, a long snout and a long tail.
Size and Weight
Seadragons grow to a length of 8-18 inches (20-45 cm).
Color
The leafy seadragon is yellow to brown and has small green dots. The weedy seadragon is reddish and has yellow and purple stripes. The ruby seadragon is - as the name suggests - reddish in color.
No Prehensile Tail
Seadragons and seahorses both have long tails. But only the seahorse can use it for grasping. The seadragon can't use it to hold on. The only exception is the red sea dragon.
Mimicry
When an animal looks like another animal or like a plant, it is called mimicry. In the seadragon, mimicry serves as camouflage. The leafy seadragon, for example, has numerous appendages that resemble kelp or seaweed. In the weedy seadragon the appendages look like twigs with small leaves. Predators mistake the fish for plants and swim past them without realizing their presence.
Seadragon or Seahorse – What’s the Difference?
Seadragons and seahorses are closely related. They both belong to the pipefish family. Some species look very similar. However, there are various differences. For example, seahorses have a tail that they can use to hold onl. Among the seadragons, only the ruby seadragon has a prehensile tail. While seahorses live in almost all seas, seadragons are only found in the coastal waters of South Australia.
Seadragon or Ghost Pipefish – What’s the Difference?
Ghost pipefish, like seaweeds, are pipefish and closely related to one another. Their appearance is quite alike as they have an elongated body along with a lengthy snout and tail. They use mimicry as their camouflage technique, too, making their bodies look like plants. However, ghost pipefish are much smaller. They don't live in Australia, but in the Pacific and Indian Oceans. Their fins are much better developed and stronger than those of the seadragons. In ghost pipefish the female incubates the eggs until they hatch.
Diet
Seadragons are carnivores. They feed on small crustaceans, larvae, fish, shrimp, worms and plankton.
Behavior
Hunting
Seadragons are ambush hunters. They hide and wait for prey to swim by. Because of their narrow, straw-like mouths, they can't hunt large prey. Their food must fit in it. They can't chew their prey either, because they don't have teeth. They need to swallow it whole.
Senses and Abilities
Swimming
Seadragons are weak swimmers. They're moving at a very slow pace, drifting with the currents most of the time. When they want to change direction, they use their tiny pectoral and dorsal fins. These are transparent and nearly invisible. That's why it seems as if the fish are floating through the water.
Diving
Seadragons usually stay at a depth of 30 feet (10 meters), but can dive to depths of 100-160 feet (30-50 meters).
Defense
Seadragons are bad at defending themselves. They have no teeth and aren't poisonous either. Luckily, their bodies are very hard and bony, which is why predatory fish tend to choose other prey.
Are Seadragons Dangerous?
The unusual appearance of the seadragon might come off as a bit scary. Plus, it is a carnivore. However, it is completely harmless. It has no teeth for biting and it isn't poisonous.
Life Expectancy
Seadragons live 2-10 years in the wild.
Enemies and Threats
Natural Enemies
Adult seadragons have no natural enemies. Due to their amazing camouflage, they often remain undiscovered. As they are very bony and difficult to chew, they are uninteresting for many predatory fish, too. Unfortunately, things look completely different with the newly hatched babies. They're a tasty treat for many sea creatures. They haven't yet developed appendages to camouflage themselves. Plus, they all hatch together at the same time. This makes it easy for predatory fish to catch them. Only about 5% of the offspring survive.
Human Impact
The greatest danger comes from people. Seadragons are suffering from the seas becoming increasingly polluted with plastic and industrial wastewater. They're also caught illegally to be sold as pets for home aquariums. However, it is very difficult to keep them because they have a lot of needs and rarely reproduce in captivity. Additionally, they are killed to use them for traditional Chinese medicine, even though there is no scientific evidence of its efficacy.
Are Seadragons Threatened?
There is currently no information about how many seadragons exist. Their habitat is limited to the South Australian coast - contrary to the adaptable seahorses, which can be found in almost all seas worldwide. If their habitat changes due to climate change or other human influences, this species could quickly become extinct.
Importance for the Ecosystem
Little is known about the importance of seadragons for nature. Researchers believe that they contribute to the biological diversity in their habitat.
Reproduction
Seadragons reproduce like seahorses. The female typically lays between 120 to 250 eggs, which are then placed on a spongy patch of skin located under the male's tail. After 4-9 weeks the little babies hatch from their eggs. They're independent from the very first moment. However, the appendages still have to grow, which is why they are without camouflage in the first few weeks. During this time they are easy prey for many predatory fish. Only about 5% of babies survive.
The Seadragon Is Related To:
- Cornetfish
- Flying Gurnard
- Ghost Pipefish
- Seahorse
- Trumpetfish
Animals in the Same Biome:
- Australian Sea Lion
- Dwarf Penguin
- Fried Egg Jellyfish
- Rays
- Sea Cucumber
- Seahorse
- Sea Urchin
- Sea Squirts
- Sharks
- Starfish
- Tuna
- Whales
