Some whale sharks. Certain types of sea tutrles and Coral reaf fish and other marine life such as mana rays and eels.
If you mean, "are all under water creatures, sea creatures?" then no. The term SEA is for the ocean and there also can be creatures in freshwater. Also some creatures that live in water such as some snakes and sea turtles come out of the water every so often, so they are no total sea/water creatures. Fish are underwater creatures though.
To take pictures of sea creatures.
Antarctica is a continent. No sea creatures live on land.
Most sea squirts live underwater.
In prehistoric times Florida was underwater in the Siluarian Sea so you would find many sea creatures back then.
Another word for an underwater creature is a deep sea creature. Deep sea creatures include the cornuta, the giant isopod and the humpback anglerfish.
there are underwater dogs :D just kidding ! hehehehehe
sea rabbitts
Octopuses are marine animals that live in the sea.
tropical underwater
penguins
fishes