Butterfly Perch
Caesioperca lepidoptera
A plucky and social fish, Butterfly Perch form large, alluring schools over deepwater reefs and ledges at the Prom. They are opportunistic feeders that take advantage of eddies that swirl the microscopic animal life, the zooplankton, into dense shoals.

The areas of reef where this occurs are usually covered with colourful sponges and gorgonian corals, and, with the combination of pink fish, it makes a visual spectacle when diving. At night, Butterfly Perch retreat into rock crevices to sleep.

Gorgonian coral
Mopsella zimmeri
Growing to nearly a metre in height in some areas, the crazed branches of the fan-shaped gorgonian corals are a distinctive feature of the deeper walls, caves and ledges of the Prom. Orange, red or yellow in colour, gorgonians are a colony of thousands of anemone like polyps. These are retracted when not trying to capture planktonic animals. Gorgonian corals grow on an angle to the prevailing surge and currents to gain maximum exposure to passing food.

You might also see animals known as basket stars with their arms intertwined with the gorgonian's branches. At nightbasket stars use the gorgonian as a base for attachment while stretching their long multi-branched arms into the current to also catch plankton.

Weedy Seadragon
Phyllopteryx taeniolatus
Despite its fierce name, the Weedy Seadragon is a dainty, timid animal that hovers slowly and gracefully over the kelp forests where it shelters. It grows up to 46 centimetres, with long leaf-shaped flaps of skin that project out at intervals along the top and bottom of the fish enabling it to camouflage easily amongst seaweed.

Seadragons are related to pipefishes and seahorses, and, like them, it is the male that holds the eggs. With Weedy Seadragons, the tiny pink eggs can be seen stuck to the tail where they are brooded for two months. They hatch as miniature versions of the adults, but grow to 7 centimetres in three weeks. Weedy Seadragons are only found in southern Australian waters.

The Weedy Seadragon is the marine state emblem for Victoria.

Leather Kelp
Ecklonia radiata
Dense forests of Leather Kelp or Ecklonia radiata, the deepest growing of the large, brown seaweeds, blanket the reefs around the Twelve Apostles at depths between 5 and 25 metres. Beneath its fronds the surge of the waves and current is dampened, and the forest provides shelter for numerous fish species.

Ecklonia forests are home to a myriad of tiny species just as terrestrial forests are home to an abundance of insects. The dominant animals are tiny grazing bug-like creatures known as amphipods or sandhoppers and over 50,000 can be found in a square metre. Of the 50 or so species that can be found on a single Ecklonia plant, most feed on a film of microscopic plants that grow on the frond surface. Amphipods are eaten by fishes such as wrasse.

Red Velvetfish
Gnathanacanthus goetzeei
While nestled deep amongst kelp fronds, the Red Velvetfish is not easily seen by divers. They are most active at night, and if you are lucky enough to come across one hunting for crabs and octopus on the seafloor, its red colouration is brilliant in the torchlight. Without a torch or direct sunlight the fish is relatively dull in colour as red light is rapidly absorbed in seawater. The red colouration makes it appear dark assists camouflage on deeper reefs.

Red Velvetfish have a soft velvety skin and scaleless bodies. This docile fish protects itself with its venomus spines. Growing to 46 centimetres, the Red Velvetfish is only found in southern Australian waters.

Giant Cuttle
Sepia apama
The Giant Cuttle is the world's largest species of cuttle and grows to nearly 1 metre in length. They feed on fish, shrimp and crabs that they capture with two long tentacles. Cuttles are camouflage experts and are able to change their body colours and textures to blend in with their environment. Like squid and octopus, they can squirt ink to confuse predators that are looking for a snack.

Cuttles also contain an unusual shell that helps them to float in the water - these are often washed up on beaches when the animal dies. Giant Cuttles are found on rocky reefs in Southern Australia's temperate waters.