Star fish could live in the kelp, sea on the rocky floor.
star fishes live in alone and in groups
They live in salt water (the sea) Because no starfish can live in freshwater
NO
The seabed
Rays
some times the angel fishes attack the star fishes of smaller size. I lost my finger star , it is of small size and attacked by blue ring angel fish... But for angel fishes it's quite difficult to attack the big size star fishes, because of their hard skin...
fishes like whales dolphin and more big fishes can live in a aquarium
Mainly Bi-valves
No.
Fishes and aminals
well it depends if you like fish
they turn their stomach inside out and eat