A fish
no
The whale shark is one fish which is bigger than the puffer fish
they eat anything that they can find under the water where they live.
No. There is no animal that can eat something bigger than itself. A king snake has a stomach and it has limits.
No. The actually group of snakes classified as "water snakes" are non venomous. However, there are many semi aquatic and aquatic species that are venmous, but go by other names. If you see a snake and do not know what species it is, then treat it as if it might be venomous and leave it alone.
Birds, fish, and other animals bigger than itself.
The Black Swallower can eat any fish that is bigger than it's own size. I can eat bony fish. In most pictures, a Black Swallower has a snake mackerel in its transparent overstretched stomach.
yes
The grass snake is pretty small but the smallest snake in the world is the thread snake it is no bigger than a quarter.
The largest fish, the whale shark, is larger than the largest bird, the ostrich. So a fish is bigger. Of course there are many fish that are smaller than many birds.
it has big jaws
Not necessarily.