There have been whole books written on the coevolution of predators and prey.
I wouldn't say predators were the cause, but land was definitely a wide-open environment at this time--no predators, plenty of food. The evolution of fish that spent more and more time on land and eventually moved there is to be expected. Not because they just "decided" to move there but because the ones that happened to start the move succeeded so well.
"Which gave rise to the Speculasaurus: father of all modern fishies and especially the Large-Mouth Grouper."