Modifiers matching billfish:

• large,
• exotic,
• oceanic,
• larger,
• threatened,

Simple categories matching threatened:

• animal,
• predator,
• bird,
• ecosystem,
• waterfowl,
• mammal,
• billfish,
• fauna,
• waterbird,
• group,
• reptile,
• species,
• creature,
• carnivore,
• fish,
• marsupial,