Jellyfish are amongst the weirdest most fascinating of all existing marine creatures. They are not actually fish but are, rather, more like sea anemones and the different varieties of coral that have formed huge structures known as coral atolls and coral reefs. 

Even though most jellyfish are limited to existing within marine water environments, they are related to a few freshwater creatures. You may be surprised to witness hundreds or even thousands of tiny white jellyfish swarms swimming in small ponds and streams. These creatures may be only half an inch in diameter. These jellyfish usually disappear and are not seen again for a number of years or are spotted in an area many miles away. 

These creatures have been located about three times in the last fifty years in Illinois, USA. They are not formed from other jellyfish. Instead, they originate from hydroids which are small creatures that look like plants. Hydroids are permanently fixed upon various underwater objects. The eggs of jellyfish undergo a process known as the "alteration of generations" which results in the development of hydroids. 

The most well known and common freshwater relatives to jellyfish are hydras, animals that have a sac-like build and are stuck onto the surface of a film of water, underwater plants, stones and sticks. They sometimes float freely in the water. If viewed under a microscope, each individual hydra resembles an inch long piece of thread that is tattered on one end and consists of a small stick-like foot on the other end. If it is touched, it folds and contracts into a small dot of jelly which is as small as a pinhead. The tattered end that flows freely in the water is actually a circlet of either eight or six slender tentacles positioned around the opening of the hydra's mouth. The tentacles are used to trap and seize small food particles and the creatures they feed on. 




Hydras do not have ears, eyes or even brains. However, they do have a small network or nerves that enable the animal to contract and expand as it responds to its surroundings. They travel along a surface by slowly gliding along it or by using its tentacles to push itself forward. This movement is described as similar to slow motion handsprings as well as tentacles looping along the surface, 

Hydras have specialized cells within certain tentacles known as 'stinging cells' which explode even when slightly touched. This causes the victim to be severely paralyzed. The tentacles assist the creature on grabbing onto the prey and inserting it into the capacious central cavity through the mouth. After prey such as small insects, worms, young fish are chemically digested within the hydra; the parts which are not used up in the hydra's body are released outside using the mouth. 

The United States is home to eight different species of hydras. Five species in the area have a color range from orange-red to pinkish grey, two are brown in color and one species is bright green due to a type of algae that is within its body. 
Normen FAdel
Author of the article
writer and blogger, founder of jellyfish .

New of label : Jellyfish Life Cycle and Reproduction

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