These fish are a critical component of a healthy coral reef ecosystem, because, along with parrotfish, they control the algae population;
(These fish; are; a critical component of a healthy coral reef ecosystem; because, along with parrotfish, they control the algae population) (they; control; the algae population)
These fish they
are control
a critical component of a healthy coral reef ecosystem because, along with parrotfish, they control the algae population
the algae population