Finally! How's that for a great fish? Did you know that orcas can get to be about thirty feet long? I didn't! This is a male, as you can tell by his imposing six-foot dorsal fin. I considered drawing a female, as the sea is given a feminine pronoun, but I figured God would want his very greatest great fish on the job and male orcas get a bit bigger than females.
The big question for anyone who illustrates Jonah is how to draw the fish. Most modern readers imagine it as a whale, though there are a few true fish that present themselves as possible candidates, like the great white shark. Of course God could have custom-made his fish -- the text says he "prepared" it -- so it could be just about anything with fins, and I was tempted to draw an enormous betta, but no, I want to figure this out, what would I send if I were God? Sadly I soon ruled out baleen whales, as despite their great size they have tiny throats because they eat tiny things. A blue whale would choke on a full-grown prophet! But most toothed whales and fish tear their food to pieces. And also we want a species that might have been under the boat Jonah was on.
The killer whale is occasionally found in the Mediterranean, it's easily big enough to hold a grown man, and it sometimes swallows its prey whole. It also sometimes partially beaches itself to grab animals off the shore, such as seal pups or what I have to imagine are very surprised deer, and that will come in handy for the reverse process of "vomit[ing] out Jonah upon the dry land." But the real reason I chose the killer whale is that even in antiquity it was associated with death and the underworld. This is a story in which the symbolic sacrifice and death map so closely to what really happens that it's almost not an allegory at all, it almost really is a story of a man who dies and keeps up a running commentary of what it's like to be dead, and that is clearly how we're meant to understand it. The great fish is Jonah's personal portable sheol, and no existing animal fits that description like Orcinus orca, the creature whose scientific name means "whale of the kingdom of the dead." If you prefer, you can call it a grampus, a word I had only ever heard in the old phrase "blowing like a grampus" and didn't even realize referred to a real creature, but there you are, a grampus is an orca. Or, according to my slang dictionary, a blustering person. They both blow, so take your choice.
Also, you can't see a killer whale's eyes. Presumably they've got eyes, but you can't make them out. Here comes toothy eyeless death, Jonah!