How big are dragons compared to fish in wof?

I thought of it being super small compared to dragons at first but after taking in account that sloths are big enough to wrap around dragons' necks and sit on their backs, I thought that maybe regular animals are also bigger in wof, compared to real life? Or does fish stay the same? If I would want to draw a dragon woth fosh in its mouth, should I take regular fish or should I take something bigger, like tuna/dolphin etc.?