They can be as big as great white sharks, but that’s about as far as the comparison goes.
Their maximum speed is a lethargic 1.7 miles per hour, many are almost blind, and they are happy to eat rotting carcasses.
They may be common throughout the ocean, but you’ve probably never heard of them. Meet the Greenland shark.
Looking like nothing so much as a chunk of weather-beaten rock, Greenland sharks (Somniosus microcephalus) can grow up to 7.3 metres (24 feet) long, making them one of the largest of all fish, and the biggest in the Arctic.
But they prefer to live in deep, cold water, so humans rarely see them.
Studies in the Arctic have revealed a few snippets of information about Greenland sharks, and more data is now starting to come in from elsewhere.
It turns out that Greenland sharks are bizarre, and may be crucially important for the ocean ecosystem.
Greenland sharks only come close to the surface in places where the shallow water is frigid enough for them – primarily in the Arctic.
Fins with transparent membranes give the ribbonfish its name. Image Credit: Joshua Lambus.
Up to 2m long the ribbonfish is an elegant deep-sea creature.
Named for the elaborate fins that ripple delicately after them as they swim, ribbonfish from the genus Trachipterus are found all over the world.
There are six known species, and Australia’s is the southern ribbonfish, a 2m-long silvery creature with black polka dots on its sides and bright red fins.
Found off the coast of southern Queensland and South Australia, the southern ribbonfish has also set up a population off the coast of South Africa.
This fish is pretty much a taxonomic nightmare, because while it’s certainly a single species, according to the Australian Museum no one can decide whether its correct scientific name is T. jacksonensis or T. arawatae.
THIS IS ONE fish that will always be caught red-handed. Ok, bad pun, but it is an interesting fish.
Endemic to Tasmania’s eastern coast, the red handfish is so named because of its apparent use of its fins as hands, even using a type of walking motion on the seafloor.
It’s a benthic fish, preferring to hang around the sandy and rocky bottoms of the seafloor. They’ve been observed eating small crustaceans and worms.
There are two colour varieties – one with red embellishments (seen in the image above) and the other a right red all over. It grows from about 6cm to about 13.5cm long.
The red handfish was first discovered in the 1800s around Port Arthur.
In the 1980s a small population was found on the Actaeon Islands, south of Hobart, and the biggest population to date was found on a reef off Primrose Sands around Hobart (10 individuals) in the 1990s.
However, in a survey in 2005, no handfish were found in those areas.
They may be hanging on, because in 2010, three individuals were found in the Primrose Sands location.
Though the species hasn’t had a full, systematic survey of its numbers, it seems that populations are few and far between, and there’s likely to be not more than 1000 individuals in the wild, and likely only hundreds.
The red handfish was known as the Brachionichthys politus, but in 2009, it was re-categorised as Thymichthys politus.
Threats to red handfish include poaching for use as pets. Its low reproductive rate and low dispersal rate make is a challenge for the species’ survival. Fragmentation of the populations is also a challenge for reproductive success.