While we're talking about Halloween, this is the Atlantic wolffish (Anarhichas lupus), very appropriately and otherwise known as the ‘devil fish’. The hefty fish grows up to 1.5 metres long and over 20kg, and they’re named for those unmistakable fangs. If they're not scary enough, their throats are also lined with a spattering of small, serrated teeth.

The new species is member of the arapaima genus, which contains some of the world’s biggest freshwater fish that breathe air and weigh up to 200kg. Found in the central Amazon of Brazil, the new fish has been named Arapaima leptosoma and is the first new species of arapaima described since 1847.

The angry-looking deep sea angler fish has a right to be cranky. It is quite possibly the ugliest animal on the planet, and it lives in what is easily Earth's most inhospitable habitat: the lonely, lightless bottom of the sea.

There are more than 200 species of anglerfish, most of which live in the murky depths of the Atlantic and Antarctic oceans, up to a mile below the surface, although some live in shallow, tropical environments. Generally dark gray to dark brown in color, they have huge heads and enormous crescent-shaped mouths filled with sharp, translucent teeth. Some angler fish can be quite large, reaching 3.3 feet (1 meter) in length. Most however are significantly smaller, often less than a foot.

Their mouths are so big and their bo ...

Stargazer fish have their eyes situated on the tops of their heads and can bury themselves in the sediment with only their faces sticking out. Some species lure prey with a worm-shaped projection that comes out of their mouths. They are toxic and some can deliver a 50 volt shock!

The coelacanth is known as a “living fossil” because it looks very much like its ancestors from 300 million years ago. Its genome has been sequenced, and it, in fact, has been found to be evolving at a very slow rate. The genetic sequence also might help give some insight into the transition from fins to limbs.

This is a butterfly gurnard fish. They have a large bony head and a bony rostrum on the snout with a very small median notch with tiny spines.  They are sandy with reddish bands and blotches and often turn red on capture.  The greenish pectoral fins are round with bright blue spots and margins, and a roundish black blotch with a bright blue margin and scattered blue spots inside.