I thought shellfish was harvested from saltwater but recently found out some species can also be found in freshwater!
Wow, I have not seen shellfish before. How is it like?
They are invertebrates, they have so many different species as molluscs, crustaceans and echinoderms. You are missing out, they are delicious! 
That is lovely, I will like to taste some
I would love to one day see a starfish, they are so cute and there are about 1,500 different kinds! You can find them in all kind of waters, from tropical to polar!
I will also love it, in which country can I find it
Starfish
Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea. Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or basket stars. About 1,500 species of starfish occur on the seabed in all the world's oceans, from the tropics to frigid polar waters. They are found from the intertidal zone down to abyssal depths, below the surface.
Starfish are marine invertebrates. They typically have a central disc and five arms, though some species
Shellfish
Shellfish is a colloquial and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some are found in freshwater. In addition, a few species of land crabs are eaten, for example "Cardisoma guanhumi" in the Caribbean. Shellfish are among the most common food allergens.
Despite the name, "shellfish" are not actually fish, but are simply water-dwelling animals. Most