The world of fish
          
        
        
          The seahorse is the slowest fish that lives in the sea.
        
        
          
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            Scales
          
        
        
          Most fish are covered in hundreds
        
        
          of scales that overlap like roof tiles.
        
        
          Tiny animals can get under the scales
        
        
          and harm them, so fish let other
        
        
          creatures give them a regular clean.
        
        
          
            Colour
          
        
        
          Fish come in all
        
        
          colours and patterns.
        
        
          Freshwater fish and those living
        
        
          in cooler waters tend to be duller in
        
        
          colour. Tropical fish are sometimes
        
        
          incredibly bright and beautiful.
        
        
          
            Fishy features
          
        
        
          Most fish look like the
        
        
          pyjama cardinalfish on
        
        
          the left. Some however have
        
        
          a different appearance. This eel
        
        
          looks more like a snake with fins.
        
        
          Unlike a snake it has sharp teeth.
        
        
          
            Living together
          
        
        
          Fish sometimes swim
        
        
          in huge groups called
        
        
          schools. When so many
        
        
          swim together they look like
        
        
          one big fish so they are less
        
        
          likely to be attacked.
        
        
          
            The art of swimming
          
        
        
          Many fish swim like snakes slide –
        
        
          they wriggle in an ‘s’ shape. Their
        
        
          whole bodies move from side
        
        
          to side and their tails flick
        
        
          to push them forwards.
        
        
          Their fins help to
        
        
          steer them.
        
        
          Some fish can
        
        
          turn on their sides
        
        
          and roll right over.
        
        
          A few can even
        
        
          swim upside-down!
        
        
          Eels are found
        
        
          in fresh water
        
        
          and sea water.
        
        
          Colours can
        
        
          be used for
        
        
          camouflage
        
        
          or to attract
        
        
          a mate.
        
        
          
            Mandarin
          
        
        
          
            fish
          
        
        
          
            Carp