Add spaces: Allthefishes,thesmallandthebigaswell,werethrownintoapanic.Thatheavy,horriblethingsankdeeperanddeeperandgrewlongerandlonger,extendingformiles-throughtheentireocean.
All the fishes, the small and the big as well, were thrown into a panic. That heavy, horrible thing sank deeper and deeper and grew longer and longer, extending for miles - through the entire ocean.