Sea Angels are actually molluscs, which puts them in the same phylum as snails, slugs and nudibranchs. They have no shells, and are adapted to swimming free in the oceans.
They are jelly-like and mostly transparent and the largest examples are no more than two inches long. They feed on closely related species like sea butterflies and plankton.
Their feeding process is somewhat extraordinary. They have tentacles that grasp their prey when the shell opening is in the right position. They extend "hooks" into the shell opening and remove the body completely from the shell, swallowing it whole.
Read more about sea angels HERE
and HERE
