Fish
There are approximately 25,000 known species of fish, although there could be many thousands more species that have yet to be seen. A fish is a vertebrate animal. Nearly all of them are ectothermic, which means 'cold-blooded'. Fish generally have two sets of paired fins and several unpaired fins. Their bodies are covered with scales, and they need to be able to cope with the pressure of the water around and above them.
Some fish that live in pitch black conditions in very deep water, are able to withstand the immense pressure of the water above them. Some recent research appears to indicate that there are a huge number of species of fish living in very deep water, in pitch black and designed to withstand the immense pressure of the water!
 lion fish © Copyright Jens Petersen Creative Commons Licence  |
 great white shark © Copyright Terry Goss Creative Commons Licence |
Fish are abundant in all the oceans, seas, rivers and lakes, except the dead sea! There are also other waters which have been polluted by man's activities and where all the fish have been killed off!
Fish are important as food for people throughout the world. Overfishing in certain areas of the oceans have depleted fish stocks to the point where it is no longer commercially viable to fish there.
 coelacanth © Copyright JoJan Creative Commons Licence |
 striped bass © Copyright Stevenj Creative Commons Licence |
Fish farming provides supplies of fish, such as salmon and trout for the retail trade. Fish farms operat in both fresh water and sea water.
Fishing is a major recreational hobby for many people. Course water fishing takes place in fresh water lakes and rivers, and it is usual to put any fish caught back in the water.
In sea angling, a popular hobby, the fish are not usually put back!
Coral reef fish danger - Blue Planet - BBC
Go to Top