Clams and mussels thrive in the marine environment.
You boil the shelled mussels in boiling water and they are cooked when the shells split open.
There are hard-shelled & soft-shelled. There are those that live in fresh water and those that live in salt water. Hope that helps. And there are those that are big enough to bite your finger off and those that aren't. hehe
An aquatic creature
Turtle, although it goes on land to lay eggs
They Lay hard shelled eggs.
Sharks.
Nope. Guess it's a water creature. Yep, pretty sure.
The aquatic creature that has scales but no fins and is commonly found in bodies of water is a snake.
Urchin
No.
It is a mythological water creature with many heads.
hydra