How about this?
Giant peridinia subsist primarily through photosynthesis and are therefore usually unagressive. However, they attack immediately any creature that their primitive sensory organs recognize as prey; in nutrient-poor habitats, "prey" can mean nearly anything.
Looks good. Updated.
I notice you used "peridinia" as the plural, but elsewhere we have "peridinium" as both singular and plural. Which is correct? Wikipedia talks about "Peridiniales".![]()
Are basketball size creatures too big to form a swarm?
A swarm is a collection of Fine, Diminutive, or Tiny creatures.