Sea anemones

Clownfish swimming among anemone - Photo papzi / Adobe

What is a sea anemone? Anemones are beautiful marine animals with wavy tentacles, and resemble underwater flowers. They are usually brightly coloured, adopting shades of white, green, blue, orange, red or mauve, often contributing to the spectacular walls of invertebrates populating reefs. Species such as the bulb-tentacled sea anemone (Entacmaea quadricolor) and magnificent sea anemone (Heteractis magnifica) form homes for beautiful anemonefish or clownfish, which shelter from predators in the anemone’s stinging cells. Certain species of sea anemones are thought to be able to survive for 100 years or more.

Where do sea anemones live? Anemones usually attach themselves to rocks and underwater structures, although some species burrow into mud or sand.

What do they look like? One of the most common anemones around the metropolitan area is the cherry anemone (Actinia tenebrosa), a brilliant red animal that withdraws its tentacles when the tide is out, resembling a cherry. Some species in tropical areas, such as the magnificent sea anemone, can grow very large.

What they eat and how: Sea anemones are carnivores that take an unusual guise. Their beautiful flower-like tentacles have a sinister purpose. Fish, snails or crabs that blunder into these waving fronds are soon paralysed by the stinging tentacles, engulfed by the central mouth and digested within the tube-like body.

Behaviour: These animals fix themselves to reefs and other structures by the muscular disc at the base of the body. Though they usually move very little, they can creep along the bottom or may detach themselves and swim off. Anemones are closely related to jellyfish. The body is a tube-like column, which is divided internally into a number of partitions containing the digestive organs, muscles and gonads. Waste is excreted through the mouth at the top of the body in the centre of the long tentacles.

Breeding: Anemones produce fully developed young through the mouth, which usually attach themselves to a rock near the parent. As a result they are often seen in groups.

Socials

Black browed Albatross on nest - Photo David / Adobe

Albatrosses

Albatrosses are perfectly adapted to spending most of their lives at sea and riding the air currents above the ocean.

Anemonefish

Anemonefish are exquisite little fish in the tropical damselfish family. They are popular pets in aquariums, and were the main characters in the animated Disney film Finding Nemo.

Australian pelican

Australian pelicans (Pelecanus conspicillatus) are large, black and white birds with massive pouched bills. The bird’s pouch is used mainly as a ‘scoop net’ for catching small fish and shrimps.

A baler crawls along on its enormous foot - Photo Suzanne Long DBCA

Baler shell

The Baler shell is a type of large sea snail that belongs to the gastropod family Volutidae.

Blue manna crab

The blue manna crab (Portunus pelagicus) is the only ten-legged crustacean found around the entire Australian continent.

Blue-ringed octopus

Blue-ringed octopuses are molluscs and, along with their close relatives the squid and cuttlefish, are the most highly developed invertebrates.

Butterfly cod

Butterfly cod are spectacular fish with brilliant colouring and long defensive spiny fins.

Cuttlefish

Cuttlefish are not fish but molluscs. They have ten arms and a head bigger than their body. They can quickly change color to camouflage into their surroundings.

Flounder

Flounder is a group of flatfish species that are demersal fish, found at the bottom of oceans around the world. They are known for their distinctive body shape and swimming style.

Giant clam

Giant clams are the world’s largest living marine bivalve and can live 100 years or more. They stay permanently attached to one spot for life.

Great white shark

Despite being a fearsome predator, the great white shark (Carcharodon carcharias) is a threatened species.

Grey nurse shark

The grey nurse shark is a large, stout-bodied shark that can grow up to 3.6 meters in length and weigh up to 230 kilograms. It has a unique pattern of spots and stripes on its body which helps it blend into the ocean floor.

Hammerhead sharks

Hammerhead sharks are known for their unusual and distinctive structure of their heads, which are flattened and laterally extended into a “hammer” shape called a cephalofoil.

Hermit crabs

Hermit crabs are fascinating creatures that have adapted to occupy empty scavenged mollusk shells to protect their fragile exoskeletons.

Leafy sea dragon

The leafy sea dragon (Phycodurus eques) is one of three species of sea dragon found only in Australian waters and nowhere else in the world.

Mantis shrimp

Mantis shrimps are colorful marine crustaceans that have forelimbs modified to spear or stun their prey.

Moray eels

Moray eels are fascinating creatures with elongated bodies and sharp teeth. They have a second set of jaws called pharyngeal jaws that extend into their throat to help them swallow prey.

Nudibranch (Sea Slug) - Photo Jim / Adobe

Nudibranches (sea slugs)

Nudibranchs are a family of opistobranchs (sea slugs) within the phylum Mollusca (molluscs). They are found throughout the world’s oceans, but are most abundant in shallow, tropical waters. Their scientific name, Nudibranchia, means naked gills.

Oystercatcher - Photo John Sandoy / Adobe

Oystercatchers

Oystercatchers are a group of waders found on coasts worldwide. They have black upper parts and white underparts. There are 11 species of oystercatchers in the world.

Potato Cod

Potato cod is a giant fish that can weigh up to 100 kg and grow up to 2 meters long. They are found in the Indo-Pacific region and are known for their friendly nature with divers.

Red-tailed tropicbird

The red-tailed tropicbird is a seabird with almost all-white plumage, a black mask and a red bill. It also has long red tail-streamers.

Sea Snake - Photo the Ocean Agency / Adobe

Sea snakes

Sea snakes are fascinating creatures that inhabit marine environments. They are closely related to venomous terrestrial snakes in Australia.

Sea stars

Sea stars are marine invertebrates that have five arms surrounding an indistinct central disk. They feed by extending their stomach out through their mouth and digesting prey. They can live up to 35 years.

Sea urchins

Sea urchins are small, spiny, and round animals that live in all the earth’s oceans. They are protected by calcareous plates and spines and have a hard shell called a ‘test’.

Seagrasses

Seagrasses are marine plants that grow in shallow waters and form meadows in estuaries and shallow coastal waters with sandy or muddy bottoms.

Seaweeds

Seaweed is a term given to a variety of sea vegetables ranging from algae to marine plants. It is used for food and bio yarn production and has health benefits.

Healthy sea sponge on coral reef - Photo the Ocean Agency / Adobe

Sponges

Sea sponges are some of the most diverse, abundant, and simple animals in the ocean. They are normally found in the world’s oceans and seas.

Western Australian seahorse

The West Australian Seahorse is a large species that is endemic to Western Australian waters. They vary in color and grow to about 22 cm in length. They feed on minute crustaceans and plankton that drift by.