It is clear that moving in water is more difficult than in air, so fish with a need to move quickly often have elongated bodies or are shaped like cylinders or torpedoes. This shape helps reduce the amount of friction caused by moving through the water and tends to make these animals grow fast. The exact number of fish species worldwide is unknown, as it is believed that many species of fish remain undiscovered. However, scientists estimate that the total number of fish species in the world is about 33,600. 

With more than 31,900 species identified to date, about 51% of all fish species are found in freshwater — that's more than 18,000 different species. And they make up a quarter of all the vertebrates in the world. Of course, those are just the species that we know of. So, out of these species, which is http://chipteeamz.com/blogs/news/all-about-the-fastest-freshwater-fish" rel="nofollow - the fastest freshwater fish ?

I'm taking a guess this is some spam post, but because it contains some general fishy business I'll take a punt and answer.

Apologies up front if genuine question -

I think it is very subjective this post.

Is it over an ambush distance, over a fight period run whilst hooked up etc.

For my money, some of the big trout go like the clappers once initially hooked up, as do BIG carp if you can believe that!

Over short ambush distances pike and tiger fish definitely make an appearance.

Big carp are on par with bonefish when hooked up and bonefish rate up there as some of the quickest but in saltwater.

My 10cents worth......this inflation is a b!tch.