This is probably not a bug but my own stupidity. I created a world in 1.12 where spawn is no where near anybody of water in hopes that when it was updated into 1.13 snapshots or higher that new features would naturally spawn once the oceans were generated. Coral Reefs, underwater plants, and downed mobs spawn perfectly, and occasionally a small pack of Dolphins but other then that fish, squid or turtles do not spawn naturally. I recreated the world in 1.13 pre-release 3, as new world generation in pre-release 4 seems to be broken, to discover an abundance of fish. I'm hoping this is in fact a bug as I've spent months creating the original world for my server only to have one of the key features inaccessible naturally.