Random wyvern character I created for no particular reason...Didn't really intend for him to look so adorable, but oh well. One name that came to me while drawing this was Khal-H'rath...but I dunno, he doesn't quite seem to suit it.
I made the front of his jaw a little like the piscivorous dinosaurs in the Spinosauridae family - Baryonyx (one of my favorites), Spinosaurus, Suchomimus and Irritator.
I guess this dragon would eat mostly fish, and scavenge meat from carcasses it comes across. I could see this dragon living in tropical regions, like the Amazon, or on forested cliffs overlooking the ocean.

I imagine he'd be around 8 meters from nose to tail, and maybe 7 1/2 - 8 feet from ground to chin (in his current relaxed position) Standing straight without the support of his wings would probably take his height to around 12-15ft.

His hunting methods would be, I imagine, either like the Gannet;
flying to feeding frenzies in the ocean and diving down to pick off fish, or even small sharks and dolphins. Like a Gannet, he could swim to a fair depth after prey, using his webbed feet and wings to propel him down.
or like a black heron;
perched on a bank or in a river, creating shade with his wings, and then catching the fish that gather around him.
In the Amazon, he'd probably feed on small reptiles, too, such as alligators and turtles as well as birds competing for fish...and those pink river dolphins.
With fish, he'd either have to eat a hell of a lot of small fish, or hunt mainly larger catfish, Trairao, Bicuda, Arapaima, etc.

Yeah I just made most of that hunting stuff up on the spot...