Essay on Fish for eTwinning Project

1. They feed and reproduce in water. They have scales, fins and gills.

2. Habitat
Fish can be found in almost every aquatic environment (salt or
fresh water). The adaptation of fish in their environment is
greater than all others species of animals because of their great
poikilotherm. Despite the abundance of salt water covering
about 71% of the Earth's surface, various freshwater fish
somehow adapt and live in certain places and take various
names eg pelagic, afropsara, petropsara, avissaia, tropical etc.
The greatest variety of fish lives in shallow tropical seas. For example, in
an area of a few square kilometers where corals exist, we can find more
than 1.000 different species of tropical fish, whereas at the same area in
cold Northern seas the equivalent number do not exceed a dozen
different species.

3. DIET
 Generally fish are characterized as omnivores. But
most are carnivores that feed on smaller fish and other
aquatic animals that eat even smaller organisms and so
on until reaching the single-celled organisms that are
plankton, the first step of the food chain. When the
general living conditions are very satisfactory tons of
plankton exist in each square kilometers. These low
rank organisms are invisible to human eye and become
the staple food of all fish. Some species are exclusively
fed by plankton.

4. ENEMIES
 The enemies of small fish are larger fish. The enemy of
large fish is pollution and fishing.

5. Special characteristics
Originally fish were classified in only one class with the same Latin name pisces.
Today they are classified into four separate classes:
 Afetochyodi or plakoderma (aphetohyidean, or aphetohyoidec, or plakodermi)
 Chondrichthyes or chondrichtheis (chondrychtyes)
 Aktinopterygioi (actinopterygii)
 Choanichthyes (or choanichtheis) or Osteichtyes (or osteichtheis)
(choanichtheyes)
The size of adult fish varies from 1 cm to 15 meters. The smallest fish in the world
is kokkovioi in the Filipines that live in lakes and their length barely reaches 1 cm.
They have exceptional moves making an endless S curve. Their moves are also
soundless.
Typical fish like sharks, sward fish, salmon, cod fish etc. present an
hydrodynamic form to move quickly avoiding water resistance. Their moves
are facilitated by a slimy substance that covers their body which helps them to
glide through the water. Their fins that are the organs of equilibrium and
direction also help them.

6. Characteristics that endanger fish
 They are so delicious that we are forced to go and fish
them. As a result, they become less, but we acquire
better vision.

7. Thank you for your attention!