What happened to the fish when God flooded the world? I don't think they were really effected. Surely there were some evil fish out there?

Oh yes. Some fish tried to take over the planet while it was flooded, but failed due to a splinter cell within the cause. They will rise again.

You don't actually believe that Mother Goose-level story, do you?

What do you call a shark, piranha, or jellyfish, and poison water snakes? pets?

They went off to film The Little Mermaid.

People ask that question under the assumption that the ocean's salt content was always high

What do you think happened to many of them when the waters receded?

All of the fish followed "jesus" into the bible

and that is why to this very day, the whole damn thing stinks from cover to cover.

All the fresh water fish would have died. All the reef fish would have died along with all the corals that form the reefs. Many of the shallow water sea fish would have died as the rain would have made the surface water too fresh.

They were eaten by bigger fish.

The freshwater fish would have died almost immediately, as would the saltwater fish. Why? Because freshwater and saltwater would have mixed.