classification about fish

                               Fish

1. Fish live in water
2. Fish are cold blooded
3. Fish have backbone
4. Fish mainly breathe thru by their gills
5. almost all fish have fins which they use for  swimming.
6. Fish lay eggs
7. Fish have air bladder
8. Fish have scales 
9. Fish have kidney
10. Fish have guts
11. Fish have two charbeard heart 
12. Fish have intestine
13. Fish have head kidney