Marine Anemone

Interesting Facts About The Marine Anemone

Marine anemones are predatory invertebrates that are water-dwelling and closely related to jellyfish, corals and hydra.  These interesting creatures literally come in nearly every color, size and shape and certainly add quite a display and a bit of charm to any aquarium.

Most species are considered polyps, attaching themselves to a surface by their adhesive foot while others are pelagic.  This variety of marine anemone has a pedal disc and a gas chamber that permits them to float around the water upside down.

In the center of their oral disc is their mouth that is surrounded by many tentacles that are used to capture prey.  The cells on their tentacles contain organelles that are capable of stinging.  When their external sensory hair is touched, it triggers an explosion of poison into their prey or aggressor.  This is what causes the marine anemone to have that really sticky feeling.  Their poison is capable of paralyzing their prey which allows the anemone to transfer it to its mouth to digest.

Life Cycle

The marine anemone produces both egg and sperm.  The egg becomes fertilized and then grows into a planula that later becomes its own polyp.  Traditionally, they will stay in one area for as long as possible unless they are attacked or the surroundings just become unsuitable.  When this happens, they will release themselves off of their housing and swim to an improved location using a flexing motion.

There are some anemone species that are separate sexes but even with them, asexual reproduction can still occur by binary fission.  This is where the polyp simply separates itself into two halves.  They can also reproduce by pedal laceration, which is characterized by small portions of the pedal breaking off and then regenerating into tiny anemones.

Nervous System

The nerves and muscles of a marine anemone are quite simple when compared to other animals however, they are still a bit more complex than coral.  The cells in both the inner and outer layers have micro-filaments.  These are then grouped into fibers that are not real muscles since they do not suspend the way that muscles do in other animals.

In the oral disc and tentacles, there are longitudinal fibers that are capable of contracting the entire body length.  The anemone also contains circular fibers that allow it to retract itself into a sphincter for protection.

Anemones have no skeleton so they shut their mouths to stabilize themselves.  By doing this, their gastrovascular cavity remains rigid.  Although they rarely make the effort to move, they can actually swim by either flexing their body or using their tentacles.

Digestive System

The marine anemone uses its gastrovascular cavity as a stomach.  The one opening on their body acts as both their anus and their mouth so although they take food in through the opening, it is also excreted through the same spot.

The flattened pharynx is present when the mouth is open which is lined with epidermis and runs nearly the length of the creature.  The gastrovascular cavity has many chambers, all serving their own purpose in the act of digestion.

 

Caring For An Anemone

Anemones prefer a good amount of light because they receive a majority of their nutrition from special algae.  They do not do well in a tank with an abundance of organic waste so a protein skimmer is helpful.  Iron supplements are often recommended by some experts.  They prefer a water temperature of near 80 degrees Fahrenheit as well as a pH range of 8.2 to 8.4.

Some anemones will eat a few times per week while others will only eat once every couple of weeks.  Some collectors do not even feed their anemones if they know that it is eating some of the fish food.  Shrimp, scallops and clams are all recommended food choices.

When handling your anemone, always wear gloves.  If you happen to get stung, pour vinegar over the area to neutralize the sting.  Most people will only experience a mild rash but it is a good idea to keep your eye on the area to watch for an allergic reaction.