Shrimp.
Yes, the noun 'lobster' is a common noun, a general word for a type of edible, marine crustacean; a word for any lobster of any kind.
A marine crustacean that is like a shrimp and in the order Euphausiacea is called krill. Krill are found in each of the oceans on Earth.
Krill
Mantis
A copepod is a small crustacean that belongs to the group of zooplankton. They are an important component of the marine food web, serving as food for many fish and other marine animals. Copepods play a key role in marine ecosystems by cycling nutrients and energy.
Shrimp may be your answer.
The likely word here is the shelled marine crustacean, spelled "barnacle".
they eat small sea life.
That is the correct spelling of the word "lobster" (a large edible oceanic crustacean).
Crabs, and the clawlike appendages are called chilipeds.
Prawns, or shrimp, are a type of marine crustacean, which are animals.
A lobster is a marine crustacean and the word 'internal' would not apply to them - your question can not be answered.