Dragonet (family Callionymidae)

I’ve loved dragons ever since I can remember loving anything. I think they’ve always been my favourite mythical creature. So any real-life animal that is named after dragons always sparks my interest. Which is how I came across today’s group of animals, the dragonets.

Dragonets belong to the family Callionymidae, which consists of 139 fish species in nineteen genera. They live in the Indian and Pacific Oceans, and enjoy hanging around in warm, tropical waters. Dragonets are bottom dwelling fish, residing on the sandy ocean floors at depths of up to 200 meters.

Dragonets, as their name implies, are not overly large fish. The largest species of dragonet reaches lengths of only 30 cm. Many species of dragonet are brightly coloured, and have wonderful patterns along their bodies. Males and females have different colour patterns, and although the fins of all dragonets are large, males are known for having particularly impressive dorsal fins.

dragonet

A very colourful mandarin fish, look for a post on these guys in the future, they’re super cool! Image source

They may look pretty, but dragonets are not friendly fish, and males are especially aggressive during courtship and mating. They will charge each another, biting the other fish’s mouth, and twist around one another. Both their large spines and bright colours are required to achieve dominance, and thus gain access to mates. Unfortunately, this comes at a cost: males are more likely to die than females, both from fights with one another and from predation, since they are easier to find, thanks to their bright and beautiful colouration.

Reproduction in dragonets begins with courtship, with both sexes (though more commonly males) displaying to one another. Displays include spreading of the fins, as well as swimming around one another. Males will also open and close their mouths, and position themselves on top of females and rub them. Once a pair has been formed, the two prepare to spawn.

To spawn, dragonets swim upwards, rising together in a semicircular pattern. They don’t move very quickly, and have to take a rest after rising about fifteen centimetres. Once they proceed to the second part of their rising swim, the dragonets start to spawn, with both sexes releasing their gametes into the water. The buoyant eggs stay floating in the water, and travel away with the current. Once spawning is done, male dragonets go back to the depths and look for more females to mate with.

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A picturesque dragonet, looking spotty and colourful. Image source

Dragonets feed on benthic organisms, primarily small invertebrates. They have large mouths, and can extend their jaws towards their prey, sucking the unfortunate victim into their mouth. When dragonets themselves are threatened, they will bury themselves in the sand, so that only their eyes are visible. Other defences depend on the species; some spines on dragonets have been reported to be venomous, while many species are able to secrete nasty tasting substances that deter predators.

Though I picked these fish as my animal for the week because of their name, they turned out to be a lot of fun to draw too. Their bright colours and pretty patterns made a lovely subject to paint. Isn’t it nice when things work out like that?

dragonet 1

My watercolour painting of an oscillated dragonet. I decided to highlight the splash of colour on its dorsal fin by keeping the rest monochrome.

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