it was even proposed that obligate coral-feeding fishes can be used as bioindicators of the general health of a reef;
p.231; in ....
Harmelin-Vivien, 1989: 21-60 quoted in Hixon M.A.; 1997; Effects of Reef Fishes on Corals and Algae; in Birkeland C. (ed.);Life and Death of Coral Reefs; Chapman and Hall London - UK;