Fishmen are on average 10x stronger than a normal human. In comic standards that'd put him at fairly stronger than Captain America. But in One Piece standards, normal people are often times greater than comic characters.
And Arlong is(was) a beast among Fishmen considering he was the boss of his own arc. He picked up a house. And he's got Fishman Karate which has some crazy techniques like flicking water bullets.
Regular humans like Makino, Coby and helmeppo(beginning of the series), and many other non-important human characters(incluing fodders) are just regular humans. Obviously someones like Luffy and Doflamingo are superhumans even by comic book standards(wich is superhumans by real-life standards) and they are even High-Metas in Marvel.
As for Arlong flipping a house, buildings. Lizard like he was shown in his respect thread he once snapped and lifted a large tree without effort, demolished a street, lifted and swinged a ship's mast like baseball bat and once has been said to be 3 times stronger than Spidey. Plus he is sometimes bulletproof and can heal very fast.