标题和文章段落来自俩以下网站

http://www.californiasciencecenter.org/

http://www.seaworld.org/aquademics/tetra/all_about_fish.htm

"Fish Tails Tell Tales"

"The shape of the tail can be an indicator of how fast a fish usually swims.

Crescent-shaped:Fish with crescent-shaped tails are fast swimmers and constantly on the move.

Forked: Fish with forked tails are also fast swimmers, though they may not swim fast all of the time. The deeper the fork, the faster the fish can swim.

Rounded: Fish with a rounded or flattened tail are generally slow moving, but are capable of short, accurate bursts of speed."

 

References:

                  http://www.californiasciencecenter.org/

                  http://www.seaworld.org/aquademics/tetra/all_about_fish.htm