YES! they can sometimes , well actually , it depends on the type of fish because to some fish if they get cramps its a disease!
it depends what creature they are....................plants, other creatures. ex: fish, krill, bacteria, coral etc.
Nutrients, soil, fish/underwater creatures.
Being of not all creatures underwater are not fish, yes. For example a dolphin, or a shark. Fish are classified as "Tetrapod's".
Marine biology is the study of underwater creatures.
Dolphins are not fish they are mammals or air breathing creatures that live underwater and come up for air like whales . ps.dolphins are part of the whale family
Most corals have attach themselves to underwater objects and remain there for life. Some corals possess toxins that make them unappetizing to underwater creatures.
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.
seashells are the hard protective homes of underwater creatures eg. clams,whelks, mussels etc. They protect their soft bodies from being attacked by fish or eaten by other underwater creatures. As the animal grows so does the shell. Apart from hermit crabs who find an empty shell in which to reside for protection
good stuff
Anything is possible but fish probably don't get cramps after eating unless they eat something that is bad for them.
Dinosaurs were all reptiles and therefore, land dwellers. None of them could breathe underwater, although marine creatures that lived along side the dinosaurs have similarities to the dinosaurs, they weren't actually classed as dinosaurs. Therefore, no dinosaurs could breathe under the water :) EDIT Fish and some amphibians are the only vertebrates that have gills and can breath underwater. The same applies to ancient animals too.
sealife creature / sealife animals / sealife / underwater mamals / underwater creatures