Obligate corallivore
From Microcosm Aquarium Explorer
The Pacific Redfin Butterflyfish is an obligate corallivore. Scott Michael
Obligate Corallivore: (Definition) A fish or other organism that must have live coral polyps as the primary source of nutrition in its diet.
The marine butterflyfishes, Family Chaetodontidae, has many obligate corallivores.
The Orangespotted Filefish, Oxymonocanthus longirostris is another example often seen in the aquarium trade.
Because these fishes seldom accept substitute foods, they seldom survive in captive systems.