Fiji Fangblenny

Found singly or in pairs, over shallow coastal lagoons and seaward reefs rich in coral growth.
Western Central Pacific - Fiji

Combtooth Blennies are the largest family of blennies, found in both tropical and subtropical waters and freshwater habitats, as the name suggests they have comb like teeth lining their jaw, well suited for scraping food off hard surfaces!
Sabretooth Blennies have teeth to match their name!
They can be seen darting forward to sever flesh from fishes fins. (can sometimes be seen taking a swipe at divers as well) They will then dart back into their holes out of harms way.
Some Blennies will mimic cleaner wrasses to get close enough for a nip at fish.
Some Sabretooth Blennies are venomous.