So non avian dinosaurs get the lions share of discussion for the Mesozoic, but what else was going on? What kind of fish were in the rivers? Artists just draw what look like modern fish but what really was there? We're there giant catfish? Something completely crazy? What stocked the ocean? Marine reptiles had to be just a fraction of what was swimming there (besides ammonites).
Well it really depends on which of the Mesozoic’s periods you are, however a lot of fish in this era looked a lot like modern fish, but there were crazy things out there that’s for sure!
(wikimedia)
Meet Leedsichthys, which lived in the middle Jurassic alongside Liopleurodon and its kin. Oh and it’s also the largest bony fish that ever lived, or at least that we know about so far!
There were also a genus of giant fresh-water sawfish called Onchopristis in the cretaceous, presumably one of the enigmatic Spinosaurus’ possible prey items. There were also Coelacanthids all the way back to the Triassc…
And these guys:
(also from wikimedia)
Xiphactinus, scary buggers if I ever saw one. They’re from the cretaceous as well. The size of a large Great White.
Of course we could be here all day looking up weird mesozoic fish (I went for a few off the top of my head I recalled from stuff like the WWD specials), but you get the gist of it: Many of them looked like modern fish, lots of them were huge, and most of the ‘living fossils’ we’ve got today were alive back then too.
~Ryuu