Reptiles

Chinese Water Dragon

Physignathus cocincinus · also called Asian water dragon, green water dragon

Vulnerable ↓ omnivorecarnivore Rainforest Temperate forest Rivers & wetlands

A Chinese water dragon is a slender, bright green lizard with a crest down its back and a tail twice the length of its body, and it lives its life along the banks of Southeast Asian forest streams. Its whole defensive strategy is water: it sleeps on branches over a river, drops straight in when startled, and can stay submerged for twenty minutes. It also carries a small light-sensing “third eye” on the crown of its head.

Overview

The Chinese water dragon, Physignathus cocincinus, is an agamid lizard of streamside forest across southern China and mainland Southeast Asia. Adults reach about 1 metre, two thirds of it tail. It is an opportunistic omnivore, eating insects, small vertebrates, fruit, and greens, and a strong swimmer that uses water as its main refuge, diving and lying on the bottom to escape.

The third eye, and running upright

Between its real eyes is a parietal eye — a simple light-and-day-length sensor under a translucent scale that helps set the lizard’s basking behaviour and internal clock. On land, a startled water dragon can sprint on its hind legs for a short distance with its tail raised for balance.

A hard pet

Chinese water dragons are sold cheaply and often small, but they are difficult to keep. They need a tall (1.8 m+), planted, humid enclosure with a big submersible pool, strong UVB, and a quiet location — a nervous dragon in a small or busy setup rubs its snout raw against the glass trying to escape.

Status

Reassessed as Vulnerable in 2018 and decreasing, after evidence of steep declines from collection for the pet trade, food, and traditional medicine and the loss of riverside forest across Vietnam and southern China. It is now protected in parts of its range and captive-bred, though wild-caught animals still enter the trade.

Chinese Water Dragon: common questions

Do Chinese water dragons really have a third eye?

Yes, though it is not an eye you can see out of. On top of the head, roughly between and behind the two normal eyes, is a parietal eye, a small organ covered by a translucent scale that contains a rudimentary lens, a retina, and a nerve connecting it to the brain. It cannot form an image, but it detects the brightness and direction of light and the length of the day, and it feeds into the systems that control basking behaviour, body temperature, seasonal hormone cycles, and the animal's internal clock. Many lizards, along with tuataras and some fish and amphibians, have one; it is an ancient feature that mammals and birds have lost.

Are Chinese water dragons good pets?

They are popular but are not a good beginner reptile, and many die young from poor husbandry. An adult needs a tall, densely planted, humid enclosure at least 1.8 metres high with sturdy branches and a large pool it can fully submerge in, plus strong UVB lighting, warm temperatures, and, crucially, a quiet, low-traffic location. Water dragons are nervous and, when kept in a small or exposed tank or in a busy room, they repeatedly run into the glass and rub their snouts raw, causing chronic infections. A calm, well-set-up dragon can become tame and live 10 to 15 years, but the space and stability required put it beyond a casual keeper. Captive-bred animals should always be chosen over wild-caught.

What is the difference between a Chinese water dragon and a green iguana?

Both are large green arboreal lizards often sold as pets, but they are not closely related and differ in size, diet, and origin. The Chinese water dragon is an agamid from Southeast Asia, reaches about a metre with a very long thin tail, is a strong swimmer that lives beside streams, and is an omnivore that eats a lot of animal prey. The green iguana is a much larger New World iguanid from Central and South America, growing to 1.5 to 2 metres and several kilograms, is almost entirely herbivorous as an adult, has a heavier body and a prominent dewlap and dorsal crest, and is arboreal but not especially aquatic. A green iguana is a bigger, stronger, more demanding animal with a powerful tail whip and, in males, seasonal aggression.

Is a Chinese water dragon dangerous?

Not really. It has small sharp teeth and can give a bite that breaks the skin, and it will whip with its long tail and scratch with its claws if grabbed or frightened, so a defensive water dragon can draw blood, but it is not venomous and poses no serious danger to an adult. Bites and scratches carry the usual infection risk and, like all reptiles, water dragons can carry salmonella, so hand-washing after handling is important. Most bites happen to keepers who corner a stressed animal or reach into the enclosure suddenly; a settled, regularly handled dragon rarely bites.

Sources & further reading

Written by HideShark Editorial Team · reviewed by HideShark Science Desk. Published September 10, 2026. Last updated September 10, 2026.

Quick facts

Scientific name: Physignathus cocincinus
Diet: An opportunistic omnivore taking insects, spiders, worms, small fish, frogs, small reptiles, rodents, and nestling birds, along with some fruit, flowers, and leafy greens, with juveniles more insectivorous and adults adding more vertebrate prey and plant matter
Escape by water: Chinese water dragons live along forest streams and rivers, sleep on branches overhanging the water, and when threatened they drop straight in, dive, and either swim away underwater or lie still on the bottom for up to about 25 minutes, using water as their main refuge
A third eye: On the top of the head between the true eyes is a small pale scale covering a parietal eye, a light-sensitive organ with a simple lens and retina that does not form images but detects light levels and helps the lizard regulate basking, hormone cycles, and its sense of time
Long crest and longer tail: Adults have a row of tall soft spines running from the neck down the back, larger in males, and a tail that makes up about two thirds of the total length of up to a metre, used as a rudder and propeller in water and as a whip in defence
They can run on two legs: A startled water dragon on land can sprint bipedally for short distances, rearing up and running on its hind legs with the tail raised for balance, before dropping back to all fours or reaching water
A common but difficult pet: Chinese water dragons are widely sold, often cheaply and small, but they are hard to keep well, needing a tall, planted, humid enclosure at least 1.8 m high with a large water area, strong UVB, and calm surroundings, and stressed or crowded dragons repeatedly rub their snouts raw against glass and mesh trying to escape
Declining in the wild: Long treated as common, the species was reassessed as Vulnerable in 2018 after evidence of steep declines in Vietnam and southern China from collection for the pet trade and for food and traditional medicine, and from the clearing of the riverside forest it depends on
Range: Mainland Southeast Asia, from southern China including Guangxi and Yunnan through Vietnam, Laos, Cambodia, and Thailand to eastern Myanmar, in evergreen and semi-evergreen forest and bamboo along the banks of streams, rivers, and lakes from the lowlands into the hills, plus an introduced population established in Hong Kong and reports of escaped or released dragons breeding in Florida.
Conservation status: Vulnerable ↓ ≈ The Chinese water dragon was assessed as Vulnerable in 2018 with a decreasing population, a marked change from its former status, after surveys and trade data showed sharp local declines. It is heavily harvested across Vietnam, Laos, Cambodia, and southern China for the international pet trade, for local consumption as food, and for use in traditional medicine, and this is compounded by the loss and degradation of the lowland and hill forest along the rivers and streams it lives beside. It is now protected in parts of its range and is bred in captivity, though wild-caught animals still enter the trade in the wild