Modifiers matching cnidarian:

• colonial,
• pelagic,
• oceanic,
• sessile,
• marine,
• predatory,
• small,
• simple,

Simple categories matching sessile:

• benthos,
• organism,
• invertebrate,
• predator,
• protozoan,
• taxon,
• polyp,
• shellfish,
• echinoderm,
• prey,
• form,
• ciliate,
• creature,
• animal,
• fauna,
• resource,
• bivalve,
• cnidarian,
• mollusc,
• coelenterate,