In this post, we will meet a fish that looks like a dragon. We will also discuss the Sea Dragon general biology and ecology, and meet a few species.
Fish that looks like a dragon
This animal is a Sea Dragon to be more precise and has several interesting characteristics. One of the most beautiful animals in the sea, it looks a lot like a dragon and makes you think of all the medieval dragon stories we have seen in movies.
The Sea Dragons
Sea Dragons are bony fish of the Actinopterygii class. They belong to the Syngnathidae family, which also includes the seahorse and the pipefish.
- Phyllopteryx taeniolatus (Common Sea Dragon or Weed Sea Dragon)
The Common or Weed Sea Dragon (Phyllopteryx taeniolatus) is The Common Sea Dragon lives in shallow waters along algae beds and seagrass meadows. These animals are very sensitive and are very subject to pollution and overharvesting. For this reason, they are protected by law.
They are small fish found in the shallow coastal waters of Tasmania and other Australian waters from the East Indian Ocean to the Southwest Pacific Ocean. These animals resemble seahorses in terms of body size and shape but have small leaf-shaped fins that camouflage them from predators. They also have some protective spines along their body.
Although seahorses can grab objects with their tails, Sea Dragon tails are not prehensile. Sea Dragons move awkwardly with their dorsal fins and transparent pectorals, but they move mostly with the water current.
Their colour is brownish, with purple and red spots. Males are darker and narrower than females. Common sea dragons reach a length of 45 centimetres.
2. Phyllopteryx dewysea (Ruby Sea Dragon)
The Ruby Sea Dragon was recently discovered, in 2015. This species inhabits the coast of Western Australia. The Ruby Sea Dragon resembles the Common Sea Dragon in many ways but is red.
Scientists believe the colouration can help the animal to camouflage itself in the deeper waters, where red tones rays are more easily absorbed.
3. Phycodurus eques (Leafy Sea Dragon or Glauert’s Sea Dragon)
The Leafy Sea Dragon has numerous leaf-shaped lumps to camouflage from predators. This species lives along the south and west coasts of Australia. The Leafy Sea Dragons change colour to blend in with their surroundings. They grow to a length of 20 to 24 centimetres.
Feeding
The Sea Dragon’s mouth has no teeth, but these animals are carnivores. They use their snouts to suck up fish larvae and small crustaceans such as plankton, shrimp, and amphipods.
Presumably, several species would eat Sea Dragons, but their camouflage is enough to protect them from most predatory attacks.
Reproduction
Except during mating season, Sea Dragons are solitary animals. They reach sexual maturity at around one to two years of age when males begin to court females.
A female produces up to 250 eggs. They are fertilized when she deposits them on the male’s tail.
The eggs settle in a region called the brood pouch, which supplies the eggs with oxygen until they hatch. As with seahorses, the male takes care of the eggs until they hatch, which takes about 9 weeks. Sea Dragons become completely independent once they hatch.
Conservation status
Weed and Leafy Sea Dragons are listed as “Least Concern” on the IUCN Red List of Endangered Species. There is insufficient data to assess the conservation status of the Ruby Sea Dragon. Some Sea Dragons are washed away by storms. Although by-catch and aquarium collection affect species, these effects are believed to be reduced in comparison to fishing activities. The most significant threats are pollution and habitat degradation/loss.
Captivity and breeding efforts
Like seahorses, Sea Dragons are difficult to raise in captivity. While it is not illegal to own one, Australia prohibits its capture from the wild environment, only with granted licenses for research and conservation efforts. It is possible to see these fascinating animals in most large aquariums and zoos.
Researchers have successfully bred the Common Sea Dragon in captivity. Although Ocean Rider in Kona, Hawaii has managed to get Leafy Sea Dragons to mate and produce eggs, no Leafy Sea Dragon has been born in captivity yet.
The Seahorses
The seahorses are close relatives to Sea Dragons. They are fish from the bony group. They are also part of the Syngnathidae family, however, members of the Hippocampus genus.
This fish has an elongated head that resembles a small horse, eyes that move independently, and great camouflage ability. Its tail allows it to cling to aquatic plants and algae, which helps with resting, camouflaging, and capturing food.
Seahorse characteristics
Seahorses live in shallow, tropical or temperate waters. They are found in estuarine environments, reefs, bays, and mangroves. These fish have an elongated head, resembling a horse, and eyes that move independently. Their mouth is tubular and has no teeth, for this reason, these fish feed by sucking. Generally, seahorses wait for some small animal to pass by to suck it up.
The body of the seahorse is small and very resistant, formed by a series of bony rings. Seahorses measure around 15 to 18 centimetres.
These fish have fins, which allow them to swim, and are active during the day, despite their small mobility. They have pectoral fins behind the operculum (plate that protects the gills), dorsal fins, which are used for propulsion, and an anal fin. They also have a prehensile tail, which is often used to cling to the substrate.
Seahorses have a very interesting feature which is the ability to change colour, as do chameleons. This ability helps them to protect against predators (camouflage). In addition, this feature assists in the breeding season, as seahorses tend to intensify their colour.
Seahorse reproduction
Seahorses have monogamous behaviour. This ends up interfering with the reproductive rate when a member of the pair is removed. In addition, they have a remarkable feature, the male is responsible for generating offspring. At the time of copulation, the female seahorse transfers her oocytes into the male’s brood pouch.
The gestation period varies from species to species and is also related to water temperature. During birth, the male squirms forcefully to release the young into the water column. More than 100 babies are born from each gestation. The recently born seahorses have 1 cm on average. Despite being small and fragile, babies are born completely independent.
Ecology
The seahorse is a carnivorous fish. They usually feed on small crustaceans such as shrimp of the Mysida order. They also feed on fish larvae and eggs, and other invertebrates such as small molluscs and worms. These animals have a high feeding frequency, due to the absence of a stomach in their digestive system.
Seahorses can feed between 30-50 times a day during adulthood. While babies, seahorses can ingest up to 3,000 organic particles (usually shrimp) in a single day. Seahorses are not capable of chewing, They disintegrate their food while sucking it up. If necessary, their nuzzle can expand if the prey is large.
These animals can be found in temperate and tropical waters worldwide. Their favourite habitats are coral reefs, marine grasses, and mangroves. These animals are known as sea chameleons, as their colour can change quickly, camouflaging them with their habitat, as occurs with the species Hippocampus histrix. This camouflage assists in ambushing their prey, thus, it influences their feeding habits.
In addition to the colour changes, seahorses have also developed body appendages called Cirri, which help in their camouflage, especially among marine plants.
Differently from most fish, seahorses have a kind of exoskeleton. They do not have any scales and this exoskeleton is formed by external and hard bone plates, which are fused covering their body.
Endangered species
Seahorses are very threatened animals, mainly because of their extensive commercial exploitation and the constant habitat degradation. These animals are often sold to be placed in aquariums or for decoration purposes, or even for drug production. We cannot forget about the accidental capture of these fish in fishing gear, an important factor that contributes to its reduction.
Conclusion
In this post, we met a fish that looks like a dragon. We also discussed the Sea Dragon general biology and ecology and met a few species.
If you have any thoughts or doubts, feel free to drop us in a comment below!
Frequently Asked Questions (FAQs): Fish that looks like a dragon.
Where does the Sea Dragon live?
The Sea Dragon species inhabit shallow coastal waters of Australia from the East Indian Ocean to the Southwest Pacific Ocean.
How big is a Seahorse?
Seahorses can reach from 0.6 to 14 inches in length in adulthood.
Is a Sea Dragon a Seahorse?
No, Sea Dragons and Seahorses belong to the same family, Syngnathidae. However, they are from different genera. Seahorses belong to Hippocampus and Sea Dragons to the genera Phycodurus and Phyllopteryx.
Why is a Seahorse a fish?
Its most striking features are a bony skeleton (hence the name bony fish), operculum covering the gill chamber on both sides, caudal fin, two pairs of medial fins, terminal mouth and vesicle gaseous.
What do Sea Dragons eat?
Sea Dragons are carnivores. They feed on small crustaceans and sometimes on fish larvae and small molluscs.
How long do Sea Dragons live?
In captivity, the Sea Dragon age record is 9 years old. Seahorses are known to live only up to 5 years, relatively shorter than their relatives.
References
Douglas, R. H., Partridge, J. C., Dulai, K. S., Hunt, D. M., Mullineaux, C. W., & Hynninen, P. H. (1999). Enhanced retinal longwave sensitivity using a chlorophyll-derived photosensitiser in Malacosteus niger, a deep-sea dragon fish with far red bioluminescence. Vision Research, 39(17), 2817-2832.
Perante, N. C., Pajaro, M. G., Meeuwig, J. J., & Vincent, A. C. J. (2002). Biology of a seahorse species, Hippocampus comes in the central Philippines. Journal of Fish Biology, 60(4), 821-837.
Woods, C. M. (2002). Natural diet of the seahorse Hippocampus abdominalis. New Zealand Journal of Marine and Freshwater Research, 36(3), 655-660.
