Is the whale shark the fastest swimmer?

No it is not, but it is however the largest fish in the sea. It is still considered a shark even though its large size and therefor a fish. Whales are a completely different species and not considered a fish. Now the fastest shark is the short fin Mako, clocked at only 32 mph, but has been said to swim at speeds of over 60 mph. The fastest marine animal would be the Sailfish, but again in is only clocked at 68 mph. It could in fact go much faster than that.